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BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171107T114500
DTEND;TZID=Europe/Rome:20171107T124500
DTSTAMP:20260404T201539
CREATED:20170728T201847Z
LAST-MODIFIED:20170728T201847Z
UID:3358-1510055100-1510058700@www.oa-roma.inaf.it
SUMMARY:The BH mass - galaxy scaling relations in the local Universe: what is the role of type 2 AGN?
DESCRIPTION:Coevolutionary models that link the growth of supermassive black holes (BHs) and of their host galaxies are based on the observations of tight scaling relations between the BH mass and some properties of the host bulge. These relations have been calibrated thanks to the direct measurements of the BH mass in local galaxies and are extremely important\, used to measure BH masses at high redshift and to determine the distribution of accreted mass\, i.e. the black hole mass function.\nHowever\, these relations seem to be biased in favour of the more massive BHs\, due to a bias in the resolution of the BH sphere of influence. Hence\, there is urgent need to explore the full distribution of BH masses\, accumulating sources below 1e+7 solar masses.\nI here present the results from a systematic study performed using deep NIR (VLT and LBT) spectroscopy of a sample of ~40 type 2 active galactic nuclei (AGN)\, drawn from the complete SWIFT/BAT 70-month hard (14-195 keV) X-ray catalogue. Thanks to our new virial relation based on unbiased physical quantities\, i.e. hard X-ray luminosity and Paβ emission line FWHM\, we have been able to measure for the first time in a virial way the supermassive black hole masses of type 2 AGN\, whose values have been up today estimated using indirect proxies (e.g. from scaling relations). With direct virial masses for type 2 AGN\, we discuss\, for the first time\, if the BH-host galaxy scaling relations hold for type 2 AGN\, thus putting a missing piece to the AGN/galaxy co-evolution puzzle.
URL:https://www.oa-roma.inaf.it/event/seminar-by-federica-ricci/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171107T114500
DTEND;TZID=Europe/Rome:20171107T124500
DTSTAMP:20260404T201539
CREATED:20170728T201847Z
LAST-MODIFIED:20170728T201847Z
UID:4716-1510055100-1510058700@www.oa-roma.inaf.it
SUMMARY:The BH mass - galaxy scaling relations in the local Universe: what is the role of type 2 AGN?
DESCRIPTION:Coevolutionary models that link the growth of supermassive black holes (BHs) and of their host galaxies are based on the observations of tight scaling relations between the BH mass and some properties of the host bulge. These relations have been calibrated thanks to the direct measurements of the BH mass in local galaxies and are extremely important\, used to measure BH masses at high redshift and to determine the distribution of accreted mass\, i.e. the black hole mass function.\nHowever\, these relations seem to be biased in favour of the more massive BHs\, due to a bias in the resolution of the BH sphere of influence. Hence\, there is urgent need to explore the full distribution of BH masses\, accumulating sources below 1e+7 solar masses.\nI here present the results from a systematic study performed using deep NIR (VLT and LBT) spectroscopy of a sample of ~40 type 2 active galactic nuclei (AGN)\, drawn from the complete SWIFT/BAT 70-month hard (14-195 keV) X-ray catalogue. Thanks to our new virial relation based on unbiased physical quantities\, i.e. hard X-ray luminosity and Paβ emission line FWHM\, we have been able to measure for the first time in a virial way the supermassive black hole masses of type 2 AGN\, whose values have been up today estimated using indirect proxies (e.g. from scaling relations). With direct virial masses for type 2 AGN\, we discuss\, for the first time\, if the BH-host galaxy scaling relations hold for type 2 AGN\, thus putting a missing piece to the AGN/galaxy co-evolution puzzle.
URL:https://www.oa-roma.inaf.it/event/seminar-by-federica-ricci-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171114T114500
DTEND;TZID=Europe/Rome:20171114T124500
DTSTAMP:20260404T201539
CREATED:20170816T115844Z
LAST-MODIFIED:20170816T115844Z
UID:4721-1510659900-1510663500@www.oa-roma.inaf.it
SUMMARY:Main Sequence Multiple Populations in Large Magellanic Cloud Globular Clusters
DESCRIPTION:Six Large Magellanic Cloud (LMC) globular clusters (GCs) (NGC 1466\, NGC 1841\, NGC 2210\, NGC 2257\, Hodge 11\, and Reticulum) have been analyzed for multiple stellar populations with the Hubble Space Telescope (GO-14164). This is the first such study for ancient (ages > 13 Gyr) clusters in the LMC. We find that five out of the six GCs examined show evidence for multiple populations in the main sequence. One cluster (Hodge 11) shows irregularities in its horizontal branch that may indicate the presence of a 0.1 dex internal helium abundance spread.
URL:https://www.oa-roma.inaf.it/event/talk-by-christina-gilligan-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171114T114500
DTEND;TZID=Europe/Rome:20171114T124500
DTSTAMP:20260404T201539
CREATED:20170816T115844Z
LAST-MODIFIED:20170816T115844Z
UID:3396-1510659900-1510663500@www.oa-roma.inaf.it
SUMMARY:Main Sequence Multiple Populations in Large Magellanic Cloud Globular Clusters
DESCRIPTION:Six Large Magellanic Cloud (LMC) globular clusters (GCs) (NGC 1466\, NGC 1841\, NGC 2210\, NGC 2257\, Hodge 11\, and Reticulum) have been analyzed for multiple stellar populations with the Hubble Space Telescope (GO-14164). This is the first such study for ancient (ages > 13 Gyr) clusters in the LMC. We find that five out of the six GCs examined show evidence for multiple populations in the main sequence. One cluster (Hodge 11) shows irregularities in its horizontal branch that may indicate the presence of a 0.1 dex internal helium abundance spread.
URL:https://www.oa-roma.inaf.it/event/talk-by-christina-gilligan/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171121T114500
DTEND;TZID=Europe/Rome:20171121T124500
DTSTAMP:20260404T201539
CREATED:20170728T201958Z
LAST-MODIFIED:20170728T201958Z
UID:4717-1511264700-1511268300@www.oa-roma.inaf.it
SUMMARY:Fibrillar Structures in the Solar Chromosphere
DESCRIPTION:I present observations of dynamic\, slender bright fibrils seen in high-quality narrow-band Ca II H images from the SuFI instrument onboard the SUNRISE balloon-borne solar observatory. We have shown that these slender Ca II H fibrils (SCFs) map magnetic fields in the low solar chromosphere derived from magnetostatic extrapolation of the photospheric field obtained with SUNRISE/IMaX and SDO/HMI. Our analysis reveals the prevalence of both kink and sausage waves in the SCFs\, propagating at high-frequencies (up to 30 mHz)\, with speeds on the order of 9-15 km/s. The estimated energy flux (~ 15 kW/m^2) carried by the observed waves is marginally enough to heat the chromosphere (and perhaps the corona). Characteristics of these waves differ from those reported for other fibrillar structures\, which\, however\, were observed mainly in the upper solar chromosphere.\nFurthermore\, I present observations of fibrillar structures through the mid-to-high solar chromosphere from coordinated observations of an active region with the Interface Region Imaging Spectrograph (IRIS) explorer and the Atacama Large Millimeter/submillimeter Array (ALMA). This provides us with temperature distributions of the entire field of view at multiple chromospheric heights\, and in particular\, of the fibrillar structures. A detail comparison between fibrillar structures simultaneously observed at several millimetre and ultraviolet bands of\, e.g.\, ALMA 1.3 mm as well as IRIS Mg II h & k\, Si IV\, C II\, and O I has provided us with new insights into the nature of these thread-like structures.
URL:https://www.oa-roma.inaf.it/event/seminar-by-shahin-jafarzadeh-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171121T114500
DTEND;TZID=Europe/Rome:20171121T124500
DTSTAMP:20260404T201539
CREATED:20170728T201958Z
LAST-MODIFIED:20170728T201958Z
UID:3360-1511264700-1511268300@www.oa-roma.inaf.it
SUMMARY:Fibrillar Structures in the Solar Chromosphere
DESCRIPTION:I present observations of dynamic\, slender bright fibrils seen in high-quality narrow-band Ca II H images from the SuFI instrument onboard the SUNRISE balloon-borne solar observatory. We have shown that these slender Ca II H fibrils (SCFs) map magnetic fields in the low solar chromosphere derived from magnetostatic extrapolation of the photospheric field obtained with SUNRISE/IMaX and SDO/HMI. Our analysis reveals the prevalence of both kink and sausage waves in the SCFs\, propagating at high-frequencies (up to 30 mHz)\, with speeds on the order of 9-15 km/s. The estimated energy flux (~ 15 kW/m^2) carried by the observed waves is marginally enough to heat the chromosphere (and perhaps the corona). Characteristics of these waves differ from those reported for other fibrillar structures\, which\, however\, were observed mainly in the upper solar chromosphere.\nFurthermore\, I present observations of fibrillar structures through the mid-to-high solar chromosphere from coordinated observations of an active region with the Interface Region Imaging Spectrograph (IRIS) explorer and the Atacama Large Millimeter/submillimeter Array (ALMA). This provides us with temperature distributions of the entire field of view at multiple chromospheric heights\, and in particular\, of the fibrillar structures. A detail comparison between fibrillar structures simultaneously observed at several millimetre and ultraviolet bands of\, e.g.\, ALMA 1.3 mm as well as IRIS Mg II h & k\, Si IV\, C II\, and O I has provided us with new insights into the nature of these thread-like structures.
URL:https://www.oa-roma.inaf.it/event/seminar-by-shahin-jafarzadeh/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171128T114500
DTEND;TZID=Europe/Rome:20171128T124500
DTSTAMP:20260404T201539
CREATED:20171016T082254Z
LAST-MODIFIED:20171016T082254Z
UID:4733-1511869500-1511873100@www.oa-roma.inaf.it
SUMMARY:The other 95%: insights from strong gravitational lensing
DESCRIPTION:In the standard cosmological model ninety-five percent of the energy content of the universe consists of dark energy and dark matter. Even though their abundance seems well determined\, very little is known about their fundamental nature. I will describe how we can learn about the physics of the dark sector by studying in detail its gravitational effect on the trajectories of photons as they travel across the universe\, a phenomenon known as strong gravitational lensing. In the first part of the talk\, I will use strong gravitational lenses with a time variable background source to measure the expansion rate of the universe (Hubble constant) to 3.8% precision. This result is completely independent of the local distance ladder and the cosmic microwave background\, and thus provides a new opportunity to understand whether the tension between the two arises from systematic uncertainties or may be indicative of new physics. In the second part of the talk I will describe how strong lensing can be used to detect the presence of dark subhalos independent of their stellar content. This measurement tests a fundamental prediction of the cold dark matter model\, i.e. that galaxies should be surrounded by large numbers of dark satellite subhalos. Proof that such satellites do not exist would force a revision of the model in favor of more exotic alternatives like warm dark matter. I will conclude by discussing the exciting future of strong lensing as a tool for cosmology\, in light of the huge numbers of strong lenses that are being discovered in the current generation of wide field astronomical surveys.
URL:https://www.oa-roma.inaf.it/event/seminar-by-tommaso-treu-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171128T114500
DTEND;TZID=Europe/Rome:20171128T124500
DTSTAMP:20260404T201539
CREATED:20171016T082254Z
LAST-MODIFIED:20171016T082254Z
UID:3639-1511869500-1511873100@www.oa-roma.inaf.it
SUMMARY:The other 95%: insights from strong gravitational lensing
DESCRIPTION:In the standard cosmological model ninety-five percent of the energy content of the universe consists of dark energy and dark matter. Even though their abundance seems well determined\, very little is known about their fundamental nature. I will describe how we can learn about the physics of the dark sector by studying in detail its gravitational effect on the trajectories of photons as they travel across the universe\, a phenomenon known as strong gravitational lensing. In the first part of the talk\, I will use strong gravitational lenses with a time variable background source to measure the expansion rate of the universe (Hubble constant) to 3.8% precision. This result is completely independent of the local distance ladder and the cosmic microwave background\, and thus provides a new opportunity to understand whether the tension between the two arises from systematic uncertainties or may be indicative of new physics. In the second part of the talk I will describe how strong lensing can be used to detect the presence of dark subhalos independent of their stellar content. This measurement tests a fundamental prediction of the cold dark matter model\, i.e. that galaxies should be surrounded by large numbers of dark satellite subhalos. Proof that such satellites do not exist would force a revision of the model in favor of more exotic alternatives like warm dark matter. I will conclude by discussing the exciting future of strong lensing as a tool for cosmology\, in light of the huge numbers of strong lenses that are being discovered in the current generation of wide field astronomical surveys.
URL:https://www.oa-roma.inaf.it/event/seminar-by-tommaso-treu/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171130T114500
DTEND;TZID=Europe/Rome:20171130T124500
DTSTAMP:20260404T201539
CREATED:20171127T182520Z
LAST-MODIFIED:20171127T182520Z
UID:4737-1512042300-1512045900@www.oa-roma.inaf.it
SUMMARY:Oumuamua\, the first asteroid coming from another planetary system
DESCRIPTION:The discovery of 1I/’Oumuamua\, the first interstellar object found \ntransiting in our Solar System\, provided astronomers with an extremely \nunusual new target\, and with a few surprises. We will briefly present \nthe discovery story and the unique properties of this new temporary \nvisitor of our Solar System.
URL:https://www.oa-roma.inaf.it/event/oumuamua-the-first-asteroid-coming-from-another-planetary-system-3/
LOCATION:OAR Monte Porzio Catone – aula Gratton\, Via Frascati 33\, Roma\, RM\, 00136\, Italia
ORGANIZER;CN="OAR":MAILTO:info@oa-roma.inaf.it
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171130T114500
DTEND;TZID=Europe/Rome:20171130T124500
DTSTAMP:20260404T201539
CREATED:20171127T182520Z
LAST-MODIFIED:20171127T182520Z
UID:3774-1512042300-1512045900@www.oa-roma.inaf.it
SUMMARY:Oumuamua\, the first asteroid coming from another planetary system
DESCRIPTION:The discovery of 1I/’Oumuamua\, the first interstellar object found \ntransiting in our Solar System\, provided astronomers with an extremely \nunusual new target\, and with a few surprises. We will briefly present \nthe discovery story and the unique properties of this new temporary \nvisitor of our Solar System.
URL:https://www.oa-roma.inaf.it/event/oumuamua-the-first-asteroid-coming-from-another-planetary-system/
LOCATION:OAR Monte Porzio Catone – aula Gratton\, Via Frascati 33\, Roma\, RM\, 00136\, Italia
ORGANIZER;CN="OAR":MAILTO:info@oa-roma.inaf.it
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171130T114500
DTEND;TZID=Europe/Rome:20171130T124500
DTSTAMP:20260404T201539
CREATED:20171128T071804Z
LAST-MODIFIED:20171128T071804Z
UID:3776-1512042300-1512045900@www.oa-roma.inaf.it
SUMMARY:Oumuamua\, the first asteroid coming from another planetary system
DESCRIPTION:The discovery of 1I/’Oumuamua\, the first interstellar object found\ntransiting in our Solar System\, provided astronomers with an extremely\nunusual new target\, and with a few surprises. We will briefly present\nthe discovery story and the unique properties of this new temporary\nvisitor of our Solar System.
URL:https://www.oa-roma.inaf.it/event/oumuamua-the-first-asteroid-coming-from-another-planetary-system-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171130T114500
DTEND;TZID=Europe/Rome:20171130T124500
DTSTAMP:20260404T201539
CREATED:20171128T071804Z
LAST-MODIFIED:20171128T071804Z
UID:4738-1512042300-1512045900@www.oa-roma.inaf.it
SUMMARY:Oumuamua\, the first asteroid coming from another planetary system
DESCRIPTION:The discovery of 1I/’Oumuamua\, the first interstellar object found\ntransiting in our Solar System\, provided astronomers with an extremely\nunusual new target\, and with a few surprises. We will briefly present\nthe discovery story and the unique properties of this new temporary\nvisitor of our Solar System.
URL:https://www.oa-roma.inaf.it/event/oumuamua-the-first-asteroid-coming-from-another-planetary-system-2-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171205T114500
DTEND;TZID=Europe/Rome:20171205T124500
DTSTAMP:20260404T201539
CREATED:20170816T120046Z
LAST-MODIFIED:20170816T120046Z
UID:3398-1512474300-1512477900@www.oa-roma.inaf.it
SUMMARY:Mass loss of AGB stars and RSG in the Magellanic Clouds
DESCRIPTION:I will discuss recent work that I am involved in regarding the determination of\nthe mass-loss rates (MLRs)  of a significant sample of Asymptotic Giant Branch stars and\nRed Supergiants in the Magellanic Clouds. This mostly involves modelling the\nspectral energy distributions to obtain dust MLRs\, but we also used ALMA to detect CO emission\nin a few LMC objects. I will also discuss possible ways forward in this field
URL:https://www.oa-roma.inaf.it/event/talk-by-martin-groenewegen/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171205T114500
DTEND;TZID=Europe/Rome:20171205T124500
DTSTAMP:20260404T201539
CREATED:20170816T120046Z
LAST-MODIFIED:20170816T120046Z
UID:4722-1512474300-1512477900@www.oa-roma.inaf.it
SUMMARY:Mass loss of AGB stars and RSG in the Magellanic Clouds
DESCRIPTION:I will discuss recent work that I am involved in regarding the determination of\nthe mass-loss rates (MLRs)  of a significant sample of Asymptotic Giant Branch stars and\nRed Supergiants in the Magellanic Clouds. This mostly involves modelling the\nspectral energy distributions to obtain dust MLRs\, but we also used ALMA to detect CO emission\nin a few LMC objects. I will also discuss possible ways forward in this field
URL:https://www.oa-roma.inaf.it/event/talk-by-martin-groenewegen-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171212T114500
DTEND;TZID=Europe/Rome:20171212T124500
DTSTAMP:20260404T201539
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:20260404T201539
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
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20171219T114500
DTEND;TZID=Europe/Rome:20171219T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180109T114500
DTEND;TZID=Europe/Rome:20180109T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180112T114500
DTEND;TZID=Europe/Rome:20180112T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180116T114500
DTEND;TZID=Europe/Rome:20180116T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180123T114500
DTEND;TZID=Europe/Rome:20180123T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180125T114500
DTEND;TZID=Europe/Rome:20180125T124500
DTSTAMP:20260404T201539
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:20260404T201539
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:20180130T080000
DTEND;TZID=Europe/Rome:20180130T170000
DTSTAMP:20260404T201539
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:20260404T201539
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
END:VCALENDAR