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X-WR-CALDESC:Eventi per Osservatorio Astronomico di Roma
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BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180314T114500
DTEND;TZID=Europe/Rome:20180314T124500
DTSTAMP:20260404T201057
CREATED:20171128T072427Z
LAST-MODIFIED:20171128T072427Z
UID:3780-1521027900-1521031500@www.oa-roma.inaf.it
SUMMARY:Drag and drift - decoupling of the dust and gas phases in astrophysical flows
DESCRIPTION:Simulating the dynamics of gas and dust in various astrophysical contexts is a topic of intense research. It includes simulations of the turbulent interstellar medium (ISM)\, active galactic nuclei (AGN)\, proto-planetary discs\, and dusty stellar winds. I will focus on the ISM and dust-driven stellar winds\, however\, and only briefly mention a few other examples.\nUsing high-resolution (1024^3) simulations of homogeneous isothermal hydrodynamic turbulence\, including a multi-disperse population of 10^7 dust grains imbedded in the gas\, one may assess the efficiency of condensation\, destruction and coagulation in molecular clouds. Due to hydrodynamic drag\, large grains will decouple from a turbulent gas flow\, while small grains will tend to follow the motions of the gas. Dust grains of various sizes will also cluster and increase the rate of grain-grain interaction. This may in turn lead to turbulence-driven coagulation and fragmentation.\nIn a stellar-wind context the decoupling between gas and dust is often called “drift”\, which is referring to the fact that the two phases may develop different mean-flow velocities. In a spherically-symmetric setting\, a mean-flow model of drift is fairly simple. But there are significant 3D effects\, as well as instabilities\, which we must take into account. For instance\, dust grains of various sizes will cluster and increase the rate of grain-grain interaction. Moreover\, due to spatial separation of dust and gas\, condensation is likely less effective than in a velocity-coupled case. There are several implications for dust-driven stellar winds which arise from this. One is that the momentum-transfer efficiency (from dust to gas) of large grains may be low as they cluster where the gas is not; another is that the sublimation rate increases as grains are more exposed to the radiation field.
URL:https://www.oa-roma.inaf.it/event/seminar-by-lars-mattsson/
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180314T114500
DTEND;TZID=Europe/Rome:20180314T124500
DTSTAMP:20260404T201057
CREATED:20171128T072427Z
LAST-MODIFIED:20171128T072427Z
UID:4739-1521027900-1521031500@www.oa-roma.inaf.it
SUMMARY:Drag and drift - decoupling of the dust and gas phases in astrophysical flows
DESCRIPTION:Simulating the dynamics of gas and dust in various astrophysical contexts is a topic of intense research. It includes simulations of the turbulent interstellar medium (ISM)\, active galactic nuclei (AGN)\, proto-planetary discs\, and dusty stellar winds. I will focus on the ISM and dust-driven stellar winds\, however\, and only briefly mention a few other examples.\nUsing high-resolution (1024^3) simulations of homogeneous isothermal hydrodynamic turbulence\, including a multi-disperse population of 10^7 dust grains imbedded in the gas\, one may assess the efficiency of condensation\, destruction and coagulation in molecular clouds. Due to hydrodynamic drag\, large grains will decouple from a turbulent gas flow\, while small grains will tend to follow the motions of the gas. Dust grains of various sizes will also cluster and increase the rate of grain-grain interaction. This may in turn lead to turbulence-driven coagulation and fragmentation.\nIn a stellar-wind context the decoupling between gas and dust is often called “drift”\, which is referring to the fact that the two phases may develop different mean-flow velocities. In a spherically-symmetric setting\, a mean-flow model of drift is fairly simple. But there are significant 3D effects\, as well as instabilities\, which we must take into account. For instance\, dust grains of various sizes will cluster and increase the rate of grain-grain interaction. Moreover\, due to spatial separation of dust and gas\, condensation is likely less effective than in a velocity-coupled case. There are several implications for dust-driven stellar winds which arise from this. One is that the momentum-transfer efficiency (from dust to gas) of large grains may be low as they cluster where the gas is not; another is that the sublimation rate increases as grains are more exposed to the radiation field.
URL:https://www.oa-roma.inaf.it/event/seminar-by-lars-mattsson-2/
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180306T114500
DTEND;TZID=Europe/Rome:20180306T124500
DTSTAMP:20260404T201057
CREATED:20171016T082612Z
LAST-MODIFIED:20171016T082612Z
UID:3643-1520336700-1520340300@www.oa-roma.inaf.it
SUMMARY:An experiment in Astrobiology: exploring the climate parameter space of rocky planets
DESCRIPTION:Astrobiology is a relatively new and fast-growing science\, whose main\ncharacteristic is to need expertises from different science fields.\nI’ll show how the climate of a planet influences its abitability.\nAstronomers from OATs\, climatologists from CNR and experts in\ndatabases from OATs joined their efforts to build a fast\, simplified\,\nyet effective climate model and database for extra-solar planets. I\nwill describe\nthe model\, its main feature\, its validation\, its application to a\nspecific exo-planet (Kepler 452b). I will then show how such a model\ncan be used to explore a huge parameter space and build a database\nthat can be used to characterize classes of habitable planets. I will\npoint out how this particular case is an good example of\nHigh-Throughput  Computing (HTC). Our database can also be used\, e.g.\,\nas a tool to get a first estimate of the habitability of a newly\ndiscovered rocky planet.\nThen I will describe possible future developements of such a research\nline\, including the study of the effect of the biosphere itself on the\nhabitability.
URL:https://www.oa-roma.inaf.it/event/seminar-by-giuseppe-murante/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180306T114500
DTEND;TZID=Europe/Rome:20180306T124500
DTSTAMP:20260404T201057
CREATED:20171016T082612Z
LAST-MODIFIED:20171016T082612Z
UID:4735-1520336700-1520340300@www.oa-roma.inaf.it
SUMMARY:An experiment in Astrobiology: exploring the climate parameter space of rocky planets
DESCRIPTION:Astrobiology is a relatively new and fast-growing science\, whose main\ncharacteristic is to need expertises from different science fields.\nI’ll show how the climate of a planet influences its abitability.\nAstronomers from OATs\, climatologists from CNR and experts in\ndatabases from OATs joined their efforts to build a fast\, simplified\,\nyet effective climate model and database for extra-solar planets. I\nwill describe\nthe model\, its main feature\, its validation\, its application to a\nspecific exo-planet (Kepler 452b). I will then show how such a model\ncan be used to explore a huge parameter space and build a database\nthat can be used to characterize classes of habitable planets. I will\npoint out how this particular case is an good example of\nHigh-Throughput  Computing (HTC). Our database can also be used\, e.g.\,\nas a tool to get a first estimate of the habitability of a newly\ndiscovered rocky planet.\nThen I will describe possible future developements of such a research\nline\, including the study of the effect of the biosphere itself on the\nhabitability.
URL:https://www.oa-roma.inaf.it/event/seminar-by-giuseppe-murante-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180227T114500
DTEND;TZID=Europe/Rome:20180227T124500
DTSTAMP:20260404T201057
CREATED:20170728T202348Z
LAST-MODIFIED:20170728T202348Z
UID:3366-1519731900-1519735500@www.oa-roma.inaf.it
SUMMARY:Bright and dustiest stars in the JWST era: powerful tools to constrain the recent star formation history
DESCRIPTION:With the advent of the JWST\, the horizon of our knowledgies will be amazingly enlarged\, providing an unprecedent look of a large volume of galaxies with a broad properties range. This will be possible in the IR domain where the extinction is low and bright cool evolved stars have their emission peak. This is the case of asymptotic giant branch stars (AGB)\, luminous objects and main dust producers for the galaxy. We present how the large release of AGB+dust evolutionary models developed in the last years\, will enable a detailed study of these sources in different systems. The distribution of these objects in the IR colour-magnitude diagrams is a powerful instrument to determine the recent star formation history of the galaxy in detail.
URL:https://www.oa-roma.inaf.it/event/seminar-by-flavia-dellagli/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180227T114500
DTEND;TZID=Europe/Rome:20180227T124500
DTSTAMP:20260404T201057
CREATED:20170728T202348Z
LAST-MODIFIED:20170728T202348Z
UID:4720-1519731900-1519735500@www.oa-roma.inaf.it
SUMMARY:Bright and dustiest stars in the JWST era: powerful tools to constrain the recent star formation history
DESCRIPTION:With the advent of the JWST\, the horizon of our knowledgies will be amazingly enlarged\, providing an unprecedent look of a large volume of galaxies with a broad properties range. This will be possible in the IR domain where the extinction is low and bright cool evolved stars have their emission peak. This is the case of asymptotic giant branch stars (AGB)\, luminous objects and main dust producers for the galaxy. We present how the large release of AGB+dust evolutionary models developed in the last years\, will enable a detailed study of these sources in different systems. The distribution of these objects in the IR colour-magnitude diagrams is a powerful instrument to determine the recent star formation history of the galaxy in detail.
URL:https://www.oa-roma.inaf.it/event/seminar-by-flavia-dellagli-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20180227
DTEND;VALUE=DATE:20180228
DTSTAMP:20260404T201057
CREATED:20180220T120259Z
LAST-MODIFIED:20180220T120259Z
UID:4745-1519689600-1519775999@www.oa-roma.inaf.it
SUMMARY:Assemblea del Personale.
DESCRIPTION:RICERCATORI\, TECNICI\, AMMINISTRATIVI\, PRECARI e STRUTTURATI DELL’ INAF – OAR\n \nASSEMBLEA DEL PERSONALE\n    Martedì 27 febbraio ore 10:00\nINAF– Monte Porzio\nPer discutere di: \n1) Stabilizzazioni e Piano Fabbisogno Personale INAF 2018/2020; \n2) Contrattazione integrativa; \n3) Nuovo contratto Istruzione e Ricerca; \n4)Elezioni RSU; \n  \nSaranno presenti all’ iniziativa : \n Stefano Bernabei – Coordinatore nazionale C.d.E. INAF FLC-CGIL\nCarlo Buttarelli – Coordinatore territoriale FLC – CGIL
URL:https://www.oa-roma.inaf.it/event/assemblea-del-personale-2/
LOCATION:OAR Monte Porzio Catone – aula Gratton\, Via Frascati 33\, Roma\, RM\, 00136\, Italia
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20180227
DTEND;VALUE=DATE:20180228
DTSTAMP:20260404T201057
CREATED:20180220T120259Z
LAST-MODIFIED:20180220T120259Z
UID:4023-1519689600-1519775999@www.oa-roma.inaf.it
SUMMARY:Assemblea del Personale.
DESCRIPTION:RICERCATORI\, TECNICI\, AMMINISTRATIVI\, PRECARI e STRUTTURATI DELL’ INAF – OAR\n \nASSEMBLEA DEL PERSONALE\n    Martedì 27 febbraio ore 10:00\nINAF– Monte Porzio\nPer discutere di: \n1) Stabilizzazioni e Piano Fabbisogno Personale INAF 2018/2020; \n2) Contrattazione integrativa; \n3) Nuovo contratto Istruzione e Ricerca; \n4)Elezioni RSU; \n  \nSaranno presenti all’ iniziativa : \n Stefano Bernabei – Coordinatore nazionale C.d.E. INAF FLC-CGIL\nCarlo Buttarelli – Coordinatore territoriale FLC – CGIL
URL:https://www.oa-roma.inaf.it/event/assemblea-del-personale/
LOCATION:OAR Monte Porzio Catone – aula Gratton\, Via Frascati 33\, Roma\, RM\, 00136\, Italia
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180220T114500
DTEND;TZID=Europe/Rome:20180220T124500
DTSTAMP:20260404T201057
CREATED:20171016T082422Z
LAST-MODIFIED:20171016T082422Z
UID:3641-1519127100-1519130700@www.oa-roma.inaf.it
SUMMARY:Lyα-Lyman Continuum connection in 3.5 ≤ z ≤ 4.3 star-forming galaxies from the VUDS survey
DESCRIPTION:Understanding the processes that led to the reionization of the Universe is among the most challenging tasks of modern extra-galactic astronomy. The main responsible for this phenomenon are thought to be high redshift star-forming galaxies. However\, it is very difficult to constrain their contribution and only few detections of Lyman Continuum (LyC) emitters have been reported so far. Following theoretical models\, several so-called indirect indicators of LyC radiation have been proposed\, such as a strong Lyα emission\, a large OIII/OII ratio\, the compactness of the UV continuum and others. Using these pre-selection criteria has indeed proved to be a powerful method to identify LyC leakers at low redshift but there is a lack of consistent studies that relates these indicators to the LyC emission at high redshifts.\nWe have used ultra-deep spectra from the Vimos Ultra Deep Survey (VUDS) to investigate the LyC properties of z~4 star-forming galaxies. We initially investigated the LyC emission from a stack of ~33 sources free from foreground contamination\, selected after a very careful cleaning procedure based on the inspection of multi-wavelength high resolution HST imaging. We found for this sample a mean fesc\,rel=0.09±0.04 with no individual detections. We also observed a tentative correlation between the individual limits given in the LyC flux and the EW of the Lyα emission line. To better investigate this trend and other expected correlations with LyC properties of high redshift galaxies\, we then analysed a much larger sample of more than 200 objects also from the VUDS survey. We found evidence that LyC is strongly related to a large Lyα EW and to the UV compactness\, in agreement with theoretical expectations and observational studies at low redshift. In addition we found that galaxies with a small Lyα spatial extent have higher LyC flux compared to the rest of the population: such a correlation had never been analysed before and seems even stronger than the correlation with high Lyα EW and small UV effective radius.
URL:https://www.oa-roma.inaf.it/event/seminar-by-francesca-marchi/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180220T114500
DTEND;TZID=Europe/Rome:20180220T124500
DTSTAMP:20260404T201057
CREATED:20171016T082422Z
LAST-MODIFIED:20171016T082422Z
UID:4734-1519127100-1519130700@www.oa-roma.inaf.it
SUMMARY:Lyα-Lyman Continuum connection in 3.5 ≤ z ≤ 4.3 star-forming galaxies from the VUDS survey
DESCRIPTION:Understanding the processes that led to the reionization of the Universe is among the most challenging tasks of modern extra-galactic astronomy. The main responsible for this phenomenon are thought to be high redshift star-forming galaxies. However\, it is very difficult to constrain their contribution and only few detections of Lyman Continuum (LyC) emitters have been reported so far. Following theoretical models\, several so-called indirect indicators of LyC radiation have been proposed\, such as a strong Lyα emission\, a large OIII/OII ratio\, the compactness of the UV continuum and others. Using these pre-selection criteria has indeed proved to be a powerful method to identify LyC leakers at low redshift but there is a lack of consistent studies that relates these indicators to the LyC emission at high redshifts.\nWe have used ultra-deep spectra from the Vimos Ultra Deep Survey (VUDS) to investigate the LyC properties of z~4 star-forming galaxies. We initially investigated the LyC emission from a stack of ~33 sources free from foreground contamination\, selected after a very careful cleaning procedure based on the inspection of multi-wavelength high resolution HST imaging. We found for this sample a mean fesc\,rel=0.09±0.04 with no individual detections. We also observed a tentative correlation between the individual limits given in the LyC flux and the EW of the Lyα emission line. To better investigate this trend and other expected correlations with LyC properties of high redshift galaxies\, we then analysed a much larger sample of more than 200 objects also from the VUDS survey. We found evidence that LyC is strongly related to a large Lyα EW and to the UV compactness\, in agreement with theoretical expectations and observational studies at low redshift. In addition we found that galaxies with a small Lyα spatial extent have higher LyC flux compared to the rest of the population: such a correlation had never been analysed before and seems even stronger than the correlation with high Lyα EW and small UV effective radius.
URL:https://www.oa-roma.inaf.it/event/seminar-by-francesca-marchi-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180213T114500
DTEND;TZID=Europe/Rome:20180213T124500
DTSTAMP:20260404T201057
CREATED:20170911T152627Z
LAST-MODIFIED:20170911T152627Z
UID:4729-1518522300-1518525900@www.oa-roma.inaf.it
SUMMARY:Electromagnetic Counterparts of Gravitational Waves
DESCRIPTION:Compact binary systems composed by neutron stars (NS) and black holes (BH) are one of the principal sources of gravitational waves (GW) in the terrestrial interferometers frequency range (10 Hz -1 kHz). While BH binary coalescences are not expected in general to be accompanied by any electromagnetic signal\, detectable electromagnetic counterparts\, such as Short Gamma-Ray Bursts (SGRB) and Kilonovae\, could follow binary NS and NS-BH mergers.\nThe recent join GW and electromagnetic observation of a binary NS coalescence (GW170817) marked the down of multimessenger astronomy era that open a new way to explore the high energetic universe and test the fundamental physics under extreme conditions.\nThe coincident detection of gravitational and electromagnetic radiation is important because these messengers carry different and complementary informations: while from a GW detection it is possible to infer the masses and the spins of the binary progenitors\, electromagnetic emission is essential to localize the source\, thus enabling the host galaxy identification.\nIn this talk I will show how a joint detection of SGRB and GW from a NS-BH progenitor could be used to measure the neutron star radius and thus constrain the dense matter equation of state.\nI will also provide a brief description of isotropic electromagnetic counterpart of compact binary coalescence such as Kilonova and Spindown powered transients.
URL:https://www.oa-roma.inaf.it/event/seminar-by-stefano-ascenzi-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180213T114500
DTEND;TZID=Europe/Rome:20180213T124500
DTSTAMP:20260404T201057
CREATED:20170911T152627Z
LAST-MODIFIED:20170911T152627Z
UID:3447-1518522300-1518525900@www.oa-roma.inaf.it
SUMMARY:Electromagnetic Counterparts of Gravitational Waves
DESCRIPTION:Compact binary systems composed by neutron stars (NS) and black holes (BH) are one of the principal sources of gravitational waves (GW) in the terrestrial interferometers frequency range (10 Hz -1 kHz). While BH binary coalescences are not expected in general to be accompanied by any electromagnetic signal\, detectable electromagnetic counterparts\, such as Short Gamma-Ray Bursts (SGRB) and Kilonovae\, could follow binary NS and NS-BH mergers.\nThe recent join GW and electromagnetic observation of a binary NS coalescence (GW170817) marked the down of multimessenger astronomy era that open a new way to explore the high energetic universe and test the fundamental physics under extreme conditions.\nThe coincident detection of gravitational and electromagnetic radiation is important because these messengers carry different and complementary informations: while from a GW detection it is possible to infer the masses and the spins of the binary progenitors\, electromagnetic emission is essential to localize the source\, thus enabling the host galaxy identification.\nIn this talk I will show how a joint detection of SGRB and GW from a NS-BH progenitor could be used to measure the neutron star radius and thus constrain the dense matter equation of state.\nI will also provide a brief description of isotropic electromagnetic counterpart of compact binary coalescence such as Kilonova and Spindown powered transients.
URL:https://www.oa-roma.inaf.it/event/seminar-by-stefano-ascenzi/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180206T114500
DTEND;TZID=Europe/Rome:20180206T124500
DTSTAMP:20260404T201057
CREATED:20170816T120220Z
LAST-MODIFIED:20170816T120220Z
UID:3400-1517917500-1517921100@www.oa-roma.inaf.it
SUMMARY:A Panchromatic View of High-Redshift Quasar Host Galaxies
DESCRIPTION:While it is now widely accepted that the growth of supermassive black-holes in galaxies is fundamentally linked to the process of galaxy formation\, the host galaxies of the most luminous and massive accreting black-holes or quasars are still poorly understood. Quasars out-shine their host galaxies at most wavelengths making these studies difficult\, and the space-density of luminous quasars is also such that very wide-field surveys are required to be able to assemble statistical samples. I will present new observations of the host galaxies of a population of heavily reddened\, luminous quasars at redshifts of 2-3. Exploiting wide-field optical surveys together with the dust obscuration towards the quasar line-of-sight\, we are\, for the first time\, able to probe the rest-frame UV emission from the star-forming hosts of these high-luminosity quasars. Observations of the quasar host galaxies at sub-millimetre and millimetre wavelengths with SCUBA2\, ALMA and the VLA are also revealing complex gas morphologies\, diverse interstellar medium properties and evidence for significant over-densities and major-mergers.
URL:https://www.oa-roma.inaf.it/event/talk-by-manda-banerji/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180206T114500
DTEND;TZID=Europe/Rome:20180206T124500
DTSTAMP:20260404T201057
CREATED:20170816T120220Z
LAST-MODIFIED:20170816T120220Z
UID:4723-1517917500-1517921100@www.oa-roma.inaf.it
SUMMARY:A Panchromatic View of High-Redshift Quasar Host Galaxies
DESCRIPTION:While it is now widely accepted that the growth of supermassive black-holes in galaxies is fundamentally linked to the process of galaxy formation\, the host galaxies of the most luminous and massive accreting black-holes or quasars are still poorly understood. Quasars out-shine their host galaxies at most wavelengths making these studies difficult\, and the space-density of luminous quasars is also such that very wide-field surveys are required to be able to assemble statistical samples. I will present new observations of the host galaxies of a population of heavily reddened\, luminous quasars at redshifts of 2-3. Exploiting wide-field optical surveys together with the dust obscuration towards the quasar line-of-sight\, we are\, for the first time\, able to probe the rest-frame UV emission from the star-forming hosts of these high-luminosity quasars. Observations of the quasar host galaxies at sub-millimetre and millimetre wavelengths with SCUBA2\, ALMA and the VLA are also revealing complex gas morphologies\, diverse interstellar medium properties and evidence for significant over-densities and major-mergers.
URL:https://www.oa-roma.inaf.it/event/talk-by-manda-banerji-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180130T080000
DTEND;TZID=Europe/Rome:20180130T170000
DTSTAMP:20260404T201057
CREATED:20170728T202224Z
LAST-MODIFIED:20170728T202224Z
UID:3364-1517299200-1517331600@www.oa-roma.inaf.it
SUMMARY:The wee free magnetic elements on the photosphere: a turbulent story
DESCRIPTION:The study of the dynamics of the photosphere allow us to investigate the physical processes occurring in both the interior of the Sun and in the higher layers of the solar atmosphere due the magnetic coupling between the photosphere and the corona. This field concerns many basic stellar processes such as: global dynamo\, turbulent convection and super-hot corona.\nIn this talk\, we report on the recent results on the transport of small scale magnetic field by advection/diffusion as seen on different data-sets from ground-based and space telescopes. We compare those results with simplified advective models that mimic the motion scales observed on the solar surface.\nWe will digress on how the advection of the smallest magnetic elements on the solar surface affects the toroidal-to-poloidal conversion in the solar cycle\, on how it can be used to estimate the possible nano-flare contribution to the coronal heating and on its consequences on transiting exo-planet detection.
URL:https://www.oa-roma.inaf.it/event/seminar-by-dario-del-moro/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180130T080000
DTEND;TZID=Europe/Rome:20180130T170000
DTSTAMP:20260404T201057
CREATED:20170728T202224Z
LAST-MODIFIED:20170728T202224Z
UID:4719-1517299200-1517331600@www.oa-roma.inaf.it
SUMMARY:The wee free magnetic elements on the photosphere: a turbulent story
DESCRIPTION:The study of the dynamics of the photosphere allow us to investigate the physical processes occurring in both the interior of the Sun and in the higher layers of the solar atmosphere due the magnetic coupling between the photosphere and the corona. This field concerns many basic stellar processes such as: global dynamo\, turbulent convection and super-hot corona.\nIn this talk\, we report on the recent results on the transport of small scale magnetic field by advection/diffusion as seen on different data-sets from ground-based and space telescopes. We compare those results with simplified advective models that mimic the motion scales observed on the solar surface.\nWe will digress on how the advection of the smallest magnetic elements on the solar surface affects the toroidal-to-poloidal conversion in the solar cycle\, on how it can be used to estimate the possible nano-flare contribution to the coronal heating and on its consequences on transiting exo-planet detection.
URL:https://www.oa-roma.inaf.it/event/seminar-by-dario-del-moro-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180125T114500
DTEND;TZID=Europe/Rome:20180125T124500
DTSTAMP:20260404T201057
CREATED:20180117T053837Z
LAST-MODIFIED:20180117T053837Z
UID:3891-1516880700-1516884300@www.oa-roma.inaf.it
SUMMARY:Modern core-collapse supernova nucleosynthesis
DESCRIPTION:Massive stars and their core-collapse supernovae are key contributors to the evolution and chemical enrichment of galaxies. Despite over 50 years of research\, the explosion mechanism of core-collapse supernovae is still not fully understood\, which hinders nucleosynthesis predictions. In a previous\, proof-of-principle study\, we have established a modern method to induced explosions in spherically symmetric (otherwise non-exploding) simulations to calculate the nucleosynthesis. This method (PUSH method) includes two aspects that are crucial for nucleosynthesis: One\, the mass cut is emerging from the simulation\, consistently with the explosion energy. And two\, neutrino-interactions with matter are included. In this talk\, I will discuss the nucleosynthesis predictions from our PUSH models and put the results in the context of other nucleosynthesis predictions
URL:https://www.oa-roma.inaf.it/event/talk-by-carla-frohlich/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180125T114500
DTEND;TZID=Europe/Rome:20180125T124500
DTSTAMP:20260404T201057
CREATED:20180117T053837Z
LAST-MODIFIED:20180117T053837Z
UID:4744-1516880700-1516884300@www.oa-roma.inaf.it
SUMMARY:Modern core-collapse supernova nucleosynthesis
DESCRIPTION:Massive stars and their core-collapse supernovae are key contributors to the evolution and chemical enrichment of galaxies. Despite over 50 years of research\, the explosion mechanism of core-collapse supernovae is still not fully understood\, which hinders nucleosynthesis predictions. In a previous\, proof-of-principle study\, we have established a modern method to induced explosions in spherically symmetric (otherwise non-exploding) simulations to calculate the nucleosynthesis. This method (PUSH method) includes two aspects that are crucial for nucleosynthesis: One\, the mass cut is emerging from the simulation\, consistently with the explosion energy. And two\, neutrino-interactions with matter are included. In this talk\, I will discuss the nucleosynthesis predictions from our PUSH models and put the results in the context of other nucleosynthesis predictions
URL:https://www.oa-roma.inaf.it/event/talk-by-carla-frohlich-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180123T114500
DTEND;TZID=Europe/Rome:20180123T124500
DTSTAMP:20260404T201057
CREATED:20170907T063712Z
LAST-MODIFIED:20170907T063712Z
UID:3437-1516707900-1516711500@www.oa-roma.inaf.it
SUMMARY:Deep\, multi-band photometry of low-mass stars to reveal young clusters: a blind study of the NGC 2264 region
DESCRIPTION:The LSST survey will provide multi-epoch\, multi-wavelength (u\,g\,r\,i\,z\,y) mapping of the Southern Hemisphere\, with a single-visit depth of r~24.5 and a gain of three magnitudes by the end of the program. This unprecedented spatial coverage will enable detection of young\, pre-main sequence stars and stellar clusters down to distances of 5-10 kpc. A crucial and challenging step for spatial analyses of large stellar populations is measuring the extinction Av of individual objects. Multi-color photometry on a (r-i\, g-r) or (i-J\, r-i) diagram offers a direct solution to this issue for M-type stars: indeed\, while the color locus of early-type (< K7) stars on these diagrams is parallel to the reddening vector\, the color locus traced by M-type stars is tilted with respect to the reddening vector\, which enables a straightforward and empirical measurement of their Av. By investigating the correlation between extinction and spatial properties of M-type stars in a given field\, it is therefore possible to reconstruct the structure of the region and probe the nature of its population. In this study\, we test the method on the NGC 2264 field. We selected a 2°x2° area centered on the NGC 2264 cluster\, and collected the available r\,i\,J photometry from existing large-scale surveys (notably Pan-STARRS and UKIDSS). Then\, assuming no prior knowledge on the nature of stars in the field\, we used the (i-J\, r-i) diagram to identify and deredden M-type stars in the sample\, and the (r-i\, r) + (RA\, Dec) diagrams to investigate the nature and spatial distribution of stars as a function of their Av. We derived a non-uniform distribution of Av across the region\, and could distinguish between a diffuse field population and a clustered stellar population toward the center of the field. An a posteriori comparison between the inferred spatial density map of the clustered population and the literature census of the NGC 2264 cluster enabled us to assess the performance of the method and its predictive capability.
URL:https://www.oa-roma.inaf.it/event/seminar-by-laura-venuti/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180123T114500
DTEND;TZID=Europe/Rome:20180123T124500
DTSTAMP:20260404T201057
CREATED:20170907T063712Z
LAST-MODIFIED:20170907T063712Z
UID:4728-1516707900-1516711500@www.oa-roma.inaf.it
SUMMARY:Deep\, multi-band photometry of low-mass stars to reveal young clusters: a blind study of the NGC 2264 region
DESCRIPTION:The LSST survey will provide multi-epoch\, multi-wavelength (u\,g\,r\,i\,z\,y) mapping of the Southern Hemisphere\, with a single-visit depth of r~24.5 and a gain of three magnitudes by the end of the program. This unprecedented spatial coverage will enable detection of young\, pre-main sequence stars and stellar clusters down to distances of 5-10 kpc. A crucial and challenging step for spatial analyses of large stellar populations is measuring the extinction Av of individual objects. Multi-color photometry on a (r-i\, g-r) or (i-J\, r-i) diagram offers a direct solution to this issue for M-type stars: indeed\, while the color locus of early-type (< K7) stars on these diagrams is parallel to the reddening vector\, the color locus traced by M-type stars is tilted with respect to the reddening vector\, which enables a straightforward and empirical measurement of their Av. By investigating the correlation between extinction and spatial properties of M-type stars in a given field\, it is therefore possible to reconstruct the structure of the region and probe the nature of its population. In this study\, we test the method on the NGC 2264 field. We selected a 2°x2° area centered on the NGC 2264 cluster\, and collected the available r\,i\,J photometry from existing large-scale surveys (notably Pan-STARRS and UKIDSS). Then\, assuming no prior knowledge on the nature of stars in the field\, we used the (i-J\, r-i) diagram to identify and deredden M-type stars in the sample\, and the (r-i\, r) + (RA\, Dec) diagrams to investigate the nature and spatial distribution of stars as a function of their Av. We derived a non-uniform distribution of Av across the region\, and could distinguish between a diffuse field population and a clustered stellar population toward the center of the field. An a posteriori comparison between the inferred spatial density map of the clustered population and the literature census of the NGC 2264 cluster enabled us to assess the performance of the method and its predictive capability.
URL:https://www.oa-roma.inaf.it/event/seminar-by-laura-venuti-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180116T114500
DTEND;TZID=Europe/Rome:20180116T124500
DTSTAMP:20260404T201057
CREATED:20170917T091053Z
LAST-MODIFIED:20170917T091053Z
UID:3513-1516103100-1516106700@www.oa-roma.inaf.it
SUMMARY:Rossby number calculations for fully convective stars
DESCRIPTION:The Rossby number is a quantity that gauges the relative importance of\nrotation in astrophysical flows. In particular\, it plays a significant role\nin mean-field\, alpha-Omega dynamo models as it is directly related to the\n“dynamo number” which\, in turn\, measures the efficiency of the magnetic field\ngeneration. From an observational standpoint\, the Rossby number has been\nwidely used to correlate either coronal or chromospheric magnetic activity of\nlow-mass stars with their rotation. A fundamental problem with this\nrotation-activity relationship is the determination of the convective turnover\ntime tau_c\, on which the Rossby number depends\, and that can be obtained\nfrom some empirical relations or from stellar models. The ATON stellar\nevolution code has been used in the near past to calculate Rossby numbers\nfor solar-type stars and now\, in view of the recent discovery of fully\nconvective stars in the non-saturated region of the rotation-activity\nrelationship\, is being used to extend those calculations to very low mass\nstars.
URL:https://www.oa-roma.inaf.it/event/seminar-by-louiz-temistoklis-mendes/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180116T114500
DTEND;TZID=Europe/Rome:20180116T124500
DTSTAMP:20260404T201057
CREATED:20170917T091053Z
LAST-MODIFIED:20170917T091053Z
UID:4730-1516103100-1516106700@www.oa-roma.inaf.it
SUMMARY:Rossby number calculations for fully convective stars
DESCRIPTION:The Rossby number is a quantity that gauges the relative importance of\nrotation in astrophysical flows. In particular\, it plays a significant role\nin mean-field\, alpha-Omega dynamo models as it is directly related to the\n“dynamo number” which\, in turn\, measures the efficiency of the magnetic field\ngeneration. From an observational standpoint\, the Rossby number has been\nwidely used to correlate either coronal or chromospheric magnetic activity of\nlow-mass stars with their rotation. A fundamental problem with this\nrotation-activity relationship is the determination of the convective turnover\ntime tau_c\, on which the Rossby number depends\, and that can be obtained\nfrom some empirical relations or from stellar models. The ATON stellar\nevolution code has been used in the near past to calculate Rossby numbers\nfor solar-type stars and now\, in view of the recent discovery of fully\nconvective stars in the non-saturated region of the rotation-activity\nrelationship\, is being used to extend those calculations to very low mass\nstars.
URL:https://www.oa-roma.inaf.it/event/seminar-by-louiz-temistoklis-mendes-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180112T114500
DTEND;TZID=Europe/Rome:20180112T124500
DTSTAMP:20260404T201057
CREATED:20171215T072607Z
LAST-MODIFIED:20171215T072607Z
UID:3845-1515757500-1515761100@www.oa-roma.inaf.it
SUMMARY:Not all stars are the Sun: rethinking the Mixing Length
DESCRIPTION:Characterizing heat transport in stars is notoriously complicated\, and the task of reproducing the physics involved with high precision on stellar evolutionary timescales is a long-standing problem in stellar modeling. For this reason\, convection in 1-D stellar evolution codes is addressed primarily through a framework known as mixing length theory (MLT). In this simplified picture\, the efficiency of convective heat transport is encapsulated by the mixing length parameter alpha_{MLT}\, measured in pressure scale heights.\nWhile it is well understood that our nearest star is not a valid representation of stars in general\, it remains the standard procedure to calibrate alpha_{MLT} according to solar specifications\, and then to apply this value in any stellar model\, regardless of mass or composition. However\, there has been growing evidence that the use of a solar-calibrated mixing length is not always appropriate.\nIn this study\, we investigate the scope of validity of a solar-calibrated mixing length over a range of evolutionary phases and input physics for very metal-poor stars\, and find that the solar-calibrated mixing length is widely ineffective at reproducing the observed properties of such stars.
URL:https://www.oa-roma.inaf.it/event/seminar-by-meridith-joyce/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180112T114500
DTEND;TZID=Europe/Rome:20180112T124500
DTSTAMP:20260404T201057
CREATED:20171215T072607Z
LAST-MODIFIED:20171215T072607Z
UID:4743-1515757500-1515761100@www.oa-roma.inaf.it
SUMMARY:Not all stars are the Sun: rethinking the Mixing Length
DESCRIPTION:Characterizing heat transport in stars is notoriously complicated\, and the task of reproducing the physics involved with high precision on stellar evolutionary timescales is a long-standing problem in stellar modeling. For this reason\, convection in 1-D stellar evolution codes is addressed primarily through a framework known as mixing length theory (MLT). In this simplified picture\, the efficiency of convective heat transport is encapsulated by the mixing length parameter alpha_{MLT}\, measured in pressure scale heights.\nWhile it is well understood that our nearest star is not a valid representation of stars in general\, it remains the standard procedure to calibrate alpha_{MLT} according to solar specifications\, and then to apply this value in any stellar model\, regardless of mass or composition. However\, there has been growing evidence that the use of a solar-calibrated mixing length is not always appropriate.\nIn this study\, we investigate the scope of validity of a solar-calibrated mixing length over a range of evolutionary phases and input physics for very metal-poor stars\, and find that the solar-calibrated mixing length is widely ineffective at reproducing the observed properties of such stars.
URL:https://www.oa-roma.inaf.it/event/seminar-by-meridith-joyce-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180109T114500
DTEND;TZID=Europe/Rome:20180109T124500
DTSTAMP:20260404T201057
CREATED:20170728T202118Z
LAST-MODIFIED:20170728T202118Z
UID:3362-1515498300-1515501900@www.oa-roma.inaf.it
SUMMARY:Microlensing
DESCRIPTION:I will review the microlensing and pixel lensing techniques and show how they play a\nfundamental role in the searches for galactic dark matter\, in the study of the galactic structure and in\ndetecting planets around faint stars whose cahacteristics are in general not accessible to other methods.\nWe show that dedicated and well planned experiments would even allow to detect more exotic objects\nas primordial massive black holes (if any) in nearby galaxies and/or to put strong constraints on\ntheir existence.
URL:https://www.oa-roma.inaf.it/event/seminar-by-raffaella-margutti/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20180109T114500
DTEND;TZID=Europe/Rome:20180109T124500
DTSTAMP:20260404T201057
CREATED:20170728T202118Z
LAST-MODIFIED:20170728T202118Z
UID:4718-1515498300-1515501900@www.oa-roma.inaf.it
SUMMARY:Microlensing
DESCRIPTION:I will review the microlensing and pixel lensing techniques and show how they play a\nfundamental role in the searches for galactic dark matter\, in the study of the galactic structure and in\ndetecting planets around faint stars whose cahacteristics are in general not accessible to other methods.\nWe show that dedicated and well planned experiments would even allow to detect more exotic objects\nas primordial massive black holes (if any) in nearby galaxies and/or to put strong constraints on\ntheir existence.
URL:https://www.oa-roma.inaf.it/event/seminar-by-raffaella-margutti-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171219T114500
DTEND;TZID=Europe/Rome:20171219T124500
DTSTAMP:20260404T201057
CREATED:20170927T104628Z
LAST-MODIFIED:20170927T104628Z
UID:3565-1513683900-1513687500@www.oa-roma.inaf.it
SUMMARY:Dust Production from Evolved Stars in the Local Group
DESCRIPTION:Infrared observations of nearby galaxies and the Milky Way show that there are two main sources of ISM dust: the winds of evolved stars and supernovae ejecta. However\, the total dust contribution from evolved stars relative to supernovae\, and how it changes with metallicity\, is less certain. Infrared photometric and spectroscopic Spitzer Surveys of the Large and Small Magellanic Clouds (LMC\, SMC): Surveying the Agents of Galaxy Evolution (SAGE) resulted in the discovery of thousands of evolved stars. Here\, I will describe how the composition and quantity of dust produced by these stars depends on metallicity. I will also discuss how the mid-IR stellar populations of the Magellanic Clouds can be used as a template for potential observations with JWST\, and how we have applied this to our observing programs of Local Group galaxies and SN1987A with JWST
URL:https://www.oa-roma.inaf.it/event/seminar-by-olivia-jones/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171219T114500
DTEND;TZID=Europe/Rome:20171219T124500
DTSTAMP:20260404T201057
CREATED:20170927T104628Z
LAST-MODIFIED:20170927T104628Z
UID:4732-1513683900-1513687500@www.oa-roma.inaf.it
SUMMARY:Dust Production from Evolved Stars in the Local Group
DESCRIPTION:Infrared observations of nearby galaxies and the Milky Way show that there are two main sources of ISM dust: the winds of evolved stars and supernovae ejecta. However\, the total dust contribution from evolved stars relative to supernovae\, and how it changes with metallicity\, is less certain. Infrared photometric and spectroscopic Spitzer Surveys of the Large and Small Magellanic Clouds (LMC\, SMC): Surveying the Agents of Galaxy Evolution (SAGE) resulted in the discovery of thousands of evolved stars. Here\, I will describe how the composition and quantity of dust produced by these stars depends on metallicity. I will also discuss how the mid-IR stellar populations of the Magellanic Clouds can be used as a template for potential observations with JWST\, and how we have applied this to our observing programs of Local Group galaxies and SN1987A with JWST
URL:https://www.oa-roma.inaf.it/event/seminar-by-olivia-jones-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171212T114500
DTEND;TZID=Europe/Rome:20171212T124500
DTSTAMP:20260404T201057
CREATED:20170821T062018Z
LAST-MODIFIED:20170821T062018Z
UID:3408-1513079100-1513082700@www.oa-roma.inaf.it
SUMMARY:High contrast imaging and the search for young exo-planets
DESCRIPTION:High contrast imaging has enormously progressed in the last twenty years\, thanks to the development of extreme AO\, efficient coronagraph\, and various differential imaging techniques. The two frontier instruments are GPI at Gemini South and SPHERE at VLT. We are now routinely achieving contrast of better than 10^5 with a record of 4×10^6 at separations below 0.5 arcsec\, This has allowed the discovery and characterization of about a dozen young planets\, of a couple of dozens of brown dwarfs\, and direct detection of several tens disks in scattered light. These data open new windows on the very early phases of planet formation\, when disks are still present. Both theory and data indicate that while clearly planets form in the late phase of the protostellar disks\, the relation between disk and planets is very complex. Also\, the spectra we are obtaining for the young planets indicate systematic differences between young and old objects with similar temperature. I will briefly present the technological and scientific aspects of this very new and exciting science
URL:https://www.oa-roma.inaf.it/event/seminar-by-raffaele-gratton/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171212T114500
DTEND;TZID=Europe/Rome:20171212T124500
DTSTAMP:20260404T201057
CREATED:20170821T062018Z
LAST-MODIFIED:20170821T062018Z
UID:4724-1513079100-1513082700@www.oa-roma.inaf.it
SUMMARY:High contrast imaging and the search for young exo-planets
DESCRIPTION:High contrast imaging has enormously progressed in the last twenty years\, thanks to the development of extreme AO\, efficient coronagraph\, and various differential imaging techniques. The two frontier instruments are GPI at Gemini South and SPHERE at VLT. We are now routinely achieving contrast of better than 10^5 with a record of 4×10^6 at separations below 0.5 arcsec\, This has allowed the discovery and characterization of about a dozen young planets\, of a couple of dozens of brown dwarfs\, and direct detection of several tens disks in scattered light. These data open new windows on the very early phases of planet formation\, when disks are still present. Both theory and data indicate that while clearly planets form in the late phase of the protostellar disks\, the relation between disk and planets is very complex. Also\, the spectra we are obtaining for the young planets indicate systematic differences between young and old objects with similar temperature. I will briefly present the technological and scientific aspects of this very new and exciting science
URL:https://www.oa-roma.inaf.it/event/seminar-by-raffaele-gratton-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
END:VCALENDAR