World Space Observatory UltraViolet (WSO-UV) is a multipurpose space observatory, made by a 170 c... more World Space Observatory UltraViolet (WSO-UV) is a multipurpose space observatory, made by a 170 cm aperture telescope, capable of UV high-resolution spectroscopy, long slit low-resolution spectroscopy, and deep UV and optical imaging. With a nominal mission life time of 5 years, and a planned extension to 10 years, from a geosynchronous orbit with an inclination of 51.8 degrees, WSO-UV will provide observations of exceptional importance for the study of many unsolved astrophysical problems. WSO-UV is implemented in the framework of a collaboration between Russia (chair), China, Germany, Italy, Spain, and Ukraine. This book illustrates the results of the feasibility study for the Field Camera Unit (FCU), a multi-spectral radial instrument on the focal plane of WSO-UV. The book provides an overview of the key science topics that are drivers to the participation of the Italian astronomical community in the WSO-UV project. The science drivers here illustrated have been used to define th...
VISTA Variables in the V�a L�ctea (VVV) is a public ESO near-IR variability survey aimed at scann... more VISTA Variables in the V�a L�ctea (VVV) is a public ESO near-IR variability survey aimed at scanning the Milky Way Bulge and an adjacent section of the mid-plane. VVV observations started in October 2009 during ESO science verification. Regular observations for the first year of the survey have been conducted since February 2010 and will cover a total area of 520 square degrees in five passbands and five epochs. Here we address the first results obtained from the VVV Survey as well as the current status of the observations.
We derive an explicit reconstruction formula for the heat flux on the internal surface of a duct ... more We derive an explicit reconstruction formula for the heat flux on the internal surface of a duct based on external temperature data. With the heat flux at hand we determine the internal convective heat transfer coefficient. Technically, by determining explicitly the singular system of a compact operator and assuming noise-free data, the heat flux is expressed as an infinite singular value expansion, whereas for noisy data, the truncated expansion is used as regularized solution. An error bound is derived for the case where the truncation parameter is determined by the Morozov's discrepancy principle. The method has high flexibility in that it is readily adapted to the finite data case without any substantial modification. Moreover, it does not require any linear system solver and it is therefore easy to implement and extremely inexpensive when compared to existing heat transfer coefficient estimation techniques. The method is illustrated by means of numerical results using both synthetic and experimental data.
A promising method for detecting earth-sized exoplanets is the timing analysis of a known transit... more A promising method for detecting earth-sized exoplanets is the timing analysis of a known transit. The technique allows a search for variations in either the transit duration or the center induced by the perturbation of a third body, e.g. a second planet or an exomoon. By applying this method, the TASTE (The Asiago Search for Transit Timing variations of Exoplanets) project will collect high- precision, short-cadence light curves for a selected sample of transits by using imaging differential photometry at the Asiago 1.82m telescope. The first light curves show that our project can achieve a competitive timing accuracy, as well as a significant improvement of the orbital parameters. We derived refined ephemerides for HAT-P-3b and HAT-P-14b with a timing accuracy of 11 and 25s, respectively. (2 data files).
Aims. With the purpose of determining the orbital parameters of exoplanetary systems from observa... more Aims. With the purpose of determining the orbital parameters of exoplanetary systems from observational data, we have developed a software, named TRADES (TRAnsits and Dynamics of Exoplanetary Systems) to simultaneously fit observed radial velocities and transit times data. Methods. We implemented a dynamical simulator for N-body system which also fits the available data during the orbital integration and determines the best combination of the orbital parameters using grid search, $\chi^2$ minimization, genetic algorithms, particle swarm optimization, and bootstrap analysis. Results. To validate TRADES, we tested the code on a synthetic three-body system and on two real systems discovered by the Kepler mission: Kepler-9 and Kepler-11. These systems are good benchmarks to test multiple exoplanet systems showing transit time variations (TTVs) due to the gravitational interaction among planets. We have found orbital parameters of Kepler-11 planets in good agreement with the values propo...
We use Hubble Space Telescope (HST) to reach the end of the white dwarf (WD) cooling sequence (CS... more We use Hubble Space Telescope (HST) to reach the end of the white dwarf (WD) cooling sequence (CS) in the solar-metallicity open cluster NGC 6819. Our photometry and completeness tests show a sharp drop in the number of WDs along the CS at magnitudes fainter than mF606W = 26.050+/- 0.075. This implies an age of 2.25+/-0.20 Gyr, consistent with the age of 2.25+/-0.30 Gyr obtained from fits to the main-sequence turn-off. The use of different WD cooling models and initial-final-mass relations have a minor impact the WD age estimate, at the level of ~0.1 Gyr. As an important by-product of this investigation we also release, in electronic format, both the catalogue of all the detected sources and the atlases of the region (in two filters). Indeed, this patch of sky studied by HST (of size ~70 arcmin sq.) is entirely within the main Kepler-mission field, so the high-resolution images and deep catalogues will be particularly useful.
We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Teles... more We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Telescope. Currently, we are able to measure the position of a well-exposed star with a precision of $\sim$4 mas/frame in each coordinate (under 0.8 arcsec seeing conditions). We present some preliminary results here.
The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Gala... more The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established. Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34x33arcmin2 field centered on the old open cluster M 67. The two-epoch archival observations separated by 4-years and acquired with the Wide-Field Imager at the 2.2m MPG/ ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series (Anderson et al., 2006A&A...454.1029A). The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT. (1 data file).
ABSTRACT We report that optical spectra of PSN J12211796+113025 obtained on Feb. 14.93 UT with th... more ABSTRACT We report that optical spectra of PSN J12211796+113025 obtained on Feb. 14.93 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.3 nm) and on Feb. 15.11 UT with the TNG (+Dolores; 320-800 nm, resolution 1.4 nm) shows a blue continuum (Tbb ~ 15300 K) with superimposed narrow, unresolved (FWHM < 600 km/s) emission lines of H, [O II], [O III], [N II] and [S II]. However, we cannot disentangle the intrinsic transient contribution to line emissions because of the heavy contamination from nearby H II regions.
ABSTRACT Intermediate-luminosity red transients (ILRTs) are a recently recognized class of stella... more ABSTRACT Intermediate-luminosity red transients (ILRTs) are a recently recognized class of stellar eruptions with maximum luminosities between those of classical novae and supernovae. During their outbursts, which generally last a few months, they typically evolve to extremely red colors, completely unlike novae. Prototypes include the M31 "Red Variable" of 1988, V838 Mon, SN 2008S, V1309 Sco, the M99 optical transient of 2010, and the 2008 and 2010 ILRTs in the nearby spiral NGC 300. I will present recent developments in the study of ILRTs. At present, it appears that there are (at least) two separate evolutionary channels leading to ILRT outbursts: mergers of close binaries (accounting for ILRTs in old populations and possibly V838 Mon), and eruptions on stars of about 8-12 Msun, possibly due to electron-capture SNe (accounting for ILRTs in young populations).
Following the repair of the WFC in May 2009, the CCD monitoring program has been used to assess t... more Following the repair of the WFC in May 2009, the CCD monitoring program has been used to assess the stability of the detector sensitivity, low frequency flat fields, and geometric distortion. These star field observations indicate that the average sensitivity is stable to better than 1% over the lifetime of the detector, and the zeropoints derived for the -81C operating temperature (implemented in July 2006) are still accurate following SM4. These observations have also been used to verify the CCD gain and full well depths with the new ACS electronics. No significant changes to the low frequency flat fields, distortion solutions, or predicted CTE losses have been found.
Proceedings of the International Astronomical Union, 2009
We derive abundances of Fe, Na, O, α and s-elements from GIRAFFE@VLT spectra for more than 200 re... more We derive abundances of Fe, Na, O, α and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite ω Centauri. Our preliminary results are that: (i) we confirm that ω Centauri exhibits large star-to-star metallicity variation (~1.4 dex); (ii) the metallicity distribution reveals the presence of at least five stellar populations with different [Fe/H]; (iii) a distinct Na-O anticorrelation is clearly observed for the metal-poor and metal-intermediate stellar populations while apparently the anticorrelation disappears for the most metal rich populations. Interestingly the Na level grows with iron.
A new 14th magnitude star was discovered by Monard in the Sculptor Group spiral galaxy NGC 300 in... more A new 14th magnitude star was discovered by Monard in the Sculptor Group spiral galaxy NGC 300 in April 2008. At the galaxy's distance of 2.2 Mpc, the visual absolute magnitude at maximum was about -12, intermediate in brightness between classical novae and Type II core-collapse supernovae. We have imaged the transient with HST and the WFPC2 camera in June
The VISTA Variables in the Vía Láctea (VVV) survey is one of six public ESO surveys, and is now i... more The VISTA Variables in the Vía Láctea (VVV) survey is one of six public ESO surveys, and is now in its 4th year of observing. Although far from being complete, the VVV survey has already delivered many results, some directly connected to the intended science goals (detection of variables stars, microlensing events, new star clusters), others concerning more exotic objects, e.g. novae. Now, at the end of the fourth observing period, and comprising roughly 50% of the proposed observations, the actual status of the survey, as well some of the results based on the VVV data, are presented.
World Space Observatory UltraViolet (WSO-UV) is a multipurpose space observatory, made by a 170 c... more World Space Observatory UltraViolet (WSO-UV) is a multipurpose space observatory, made by a 170 cm aperture telescope, capable of UV high-resolution spectroscopy, long slit low-resolution spectroscopy, and deep UV and optical imaging. With a nominal mission life time of 5 years, and a planned extension to 10 years, from a geosynchronous orbit with an inclination of 51.8 degrees, WSO-UV will provide observations of exceptional importance for the study of many unsolved astrophysical problems. WSO-UV is implemented in the framework of a collaboration between Russia (chair), China, Germany, Italy, Spain, and Ukraine. This book illustrates the results of the feasibility study for the Field Camera Unit (FCU), a multi-spectral radial instrument on the focal plane of WSO-UV. The book provides an overview of the key science topics that are drivers to the participation of the Italian astronomical community in the WSO-UV project. The science drivers here illustrated have been used to define th...
VISTA Variables in the V�a L�ctea (VVV) is a public ESO near-IR variability survey aimed at scann... more VISTA Variables in the V�a L�ctea (VVV) is a public ESO near-IR variability survey aimed at scanning the Milky Way Bulge and an adjacent section of the mid-plane. VVV observations started in October 2009 during ESO science verification. Regular observations for the first year of the survey have been conducted since February 2010 and will cover a total area of 520 square degrees in five passbands and five epochs. Here we address the first results obtained from the VVV Survey as well as the current status of the observations.
We derive an explicit reconstruction formula for the heat flux on the internal surface of a duct ... more We derive an explicit reconstruction formula for the heat flux on the internal surface of a duct based on external temperature data. With the heat flux at hand we determine the internal convective heat transfer coefficient. Technically, by determining explicitly the singular system of a compact operator and assuming noise-free data, the heat flux is expressed as an infinite singular value expansion, whereas for noisy data, the truncated expansion is used as regularized solution. An error bound is derived for the case where the truncation parameter is determined by the Morozov's discrepancy principle. The method has high flexibility in that it is readily adapted to the finite data case without any substantial modification. Moreover, it does not require any linear system solver and it is therefore easy to implement and extremely inexpensive when compared to existing heat transfer coefficient estimation techniques. The method is illustrated by means of numerical results using both synthetic and experimental data.
A promising method for detecting earth-sized exoplanets is the timing analysis of a known transit... more A promising method for detecting earth-sized exoplanets is the timing analysis of a known transit. The technique allows a search for variations in either the transit duration or the center induced by the perturbation of a third body, e.g. a second planet or an exomoon. By applying this method, the TASTE (The Asiago Search for Transit Timing variations of Exoplanets) project will collect high- precision, short-cadence light curves for a selected sample of transits by using imaging differential photometry at the Asiago 1.82m telescope. The first light curves show that our project can achieve a competitive timing accuracy, as well as a significant improvement of the orbital parameters. We derived refined ephemerides for HAT-P-3b and HAT-P-14b with a timing accuracy of 11 and 25s, respectively. (2 data files).
Aims. With the purpose of determining the orbital parameters of exoplanetary systems from observa... more Aims. With the purpose of determining the orbital parameters of exoplanetary systems from observational data, we have developed a software, named TRADES (TRAnsits and Dynamics of Exoplanetary Systems) to simultaneously fit observed radial velocities and transit times data. Methods. We implemented a dynamical simulator for N-body system which also fits the available data during the orbital integration and determines the best combination of the orbital parameters using grid search, $\chi^2$ minimization, genetic algorithms, particle swarm optimization, and bootstrap analysis. Results. To validate TRADES, we tested the code on a synthetic three-body system and on two real systems discovered by the Kepler mission: Kepler-9 and Kepler-11. These systems are good benchmarks to test multiple exoplanet systems showing transit time variations (TTVs) due to the gravitational interaction among planets. We have found orbital parameters of Kepler-11 planets in good agreement with the values propo...
We use Hubble Space Telescope (HST) to reach the end of the white dwarf (WD) cooling sequence (CS... more We use Hubble Space Telescope (HST) to reach the end of the white dwarf (WD) cooling sequence (CS) in the solar-metallicity open cluster NGC 6819. Our photometry and completeness tests show a sharp drop in the number of WDs along the CS at magnitudes fainter than mF606W = 26.050+/- 0.075. This implies an age of 2.25+/-0.20 Gyr, consistent with the age of 2.25+/-0.30 Gyr obtained from fits to the main-sequence turn-off. The use of different WD cooling models and initial-final-mass relations have a minor impact the WD age estimate, at the level of ~0.1 Gyr. As an important by-product of this investigation we also release, in electronic format, both the catalogue of all the detected sources and the atlases of the region (in two filters). Indeed, this patch of sky studied by HST (of size ~70 arcmin sq.) is entirely within the main Kepler-mission field, so the high-resolution images and deep catalogues will be particularly useful.
We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Teles... more We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Telescope. Currently, we are able to measure the position of a well-exposed star with a precision of $\sim$4 mas/frame in each coordinate (under 0.8 arcsec seeing conditions). We present some preliminary results here.
The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Gala... more The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established. Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34x33arcmin2 field centered on the old open cluster M 67. The two-epoch archival observations separated by 4-years and acquired with the Wide-Field Imager at the 2.2m MPG/ ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series (Anderson et al., 2006A&A...454.1029A). The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT. (1 data file).
ABSTRACT We report that optical spectra of PSN J12211796+113025 obtained on Feb. 14.93 UT with th... more ABSTRACT We report that optical spectra of PSN J12211796+113025 obtained on Feb. 14.93 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.3 nm) and on Feb. 15.11 UT with the TNG (+Dolores; 320-800 nm, resolution 1.4 nm) shows a blue continuum (Tbb ~ 15300 K) with superimposed narrow, unresolved (FWHM < 600 km/s) emission lines of H, [O II], [O III], [N II] and [S II]. However, we cannot disentangle the intrinsic transient contribution to line emissions because of the heavy contamination from nearby H II regions.
ABSTRACT Intermediate-luminosity red transients (ILRTs) are a recently recognized class of stella... more ABSTRACT Intermediate-luminosity red transients (ILRTs) are a recently recognized class of stellar eruptions with maximum luminosities between those of classical novae and supernovae. During their outbursts, which generally last a few months, they typically evolve to extremely red colors, completely unlike novae. Prototypes include the M31 "Red Variable" of 1988, V838 Mon, SN 2008S, V1309 Sco, the M99 optical transient of 2010, and the 2008 and 2010 ILRTs in the nearby spiral NGC 300. I will present recent developments in the study of ILRTs. At present, it appears that there are (at least) two separate evolutionary channels leading to ILRT outbursts: mergers of close binaries (accounting for ILRTs in old populations and possibly V838 Mon), and eruptions on stars of about 8-12 Msun, possibly due to electron-capture SNe (accounting for ILRTs in young populations).
Following the repair of the WFC in May 2009, the CCD monitoring program has been used to assess t... more Following the repair of the WFC in May 2009, the CCD monitoring program has been used to assess the stability of the detector sensitivity, low frequency flat fields, and geometric distortion. These star field observations indicate that the average sensitivity is stable to better than 1% over the lifetime of the detector, and the zeropoints derived for the -81C operating temperature (implemented in July 2006) are still accurate following SM4. These observations have also been used to verify the CCD gain and full well depths with the new ACS electronics. No significant changes to the low frequency flat fields, distortion solutions, or predicted CTE losses have been found.
Proceedings of the International Astronomical Union, 2009
We derive abundances of Fe, Na, O, α and s-elements from GIRAFFE@VLT spectra for more than 200 re... more We derive abundances of Fe, Na, O, α and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite ω Centauri. Our preliminary results are that: (i) we confirm that ω Centauri exhibits large star-to-star metallicity variation (~1.4 dex); (ii) the metallicity distribution reveals the presence of at least five stellar populations with different [Fe/H]; (iii) a distinct Na-O anticorrelation is clearly observed for the metal-poor and metal-intermediate stellar populations while apparently the anticorrelation disappears for the most metal rich populations. Interestingly the Na level grows with iron.
A new 14th magnitude star was discovered by Monard in the Sculptor Group spiral galaxy NGC 300 in... more A new 14th magnitude star was discovered by Monard in the Sculptor Group spiral galaxy NGC 300 in April 2008. At the galaxy's distance of 2.2 Mpc, the visual absolute magnitude at maximum was about -12, intermediate in brightness between classical novae and Type II core-collapse supernovae. We have imaged the transient with HST and the WFPC2 camera in June
The VISTA Variables in the Vía Láctea (VVV) survey is one of six public ESO surveys, and is now i... more The VISTA Variables in the Vía Láctea (VVV) survey is one of six public ESO surveys, and is now in its 4th year of observing. Although far from being complete, the VVV survey has already delivered many results, some directly connected to the intended science goals (detection of variables stars, microlensing events, new star clusters), others concerning more exotic objects, e.g. novae. Now, at the end of the fourth observing period, and comprising roughly 50% of the proposed observations, the actual status of the survey, as well some of the results based on the VVV data, are presented.
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