Emanuela Pompei - Academia.edu (original) (raw)
Papers by Emanuela Pompei
Ground-based and Airborne Instrumentation for Astronomy IX
SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage... more SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage from U-to H-band, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory. It is designed to observe all kind of transients and variable sources discovered by different surveys with a highly flexible schedule maintained by the consortium, based on the Target of Opportunity concept. SOXS is going to be a fundamental spectroscopic partner for any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. This paper gives an updated status of the project, when the instrument is in the advanced phase of integration and testing in Europe, prior to the activities in Chile.
Summary. The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust whi... more Summary. The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2 1 to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud. 1
Ground-based and Airborne Instrumentation for Astronomy VIII, 2020
SOXS (Son Of X-Shooter) is a single object spectrograph, characterized by offering a wide simulta... more SOXS (Son Of X-Shooter) is a single object spectrograph, characterized by offering a wide simultaneous spectral coverage from U-to H-band, built by an international consortium for the 3.6-m ESO New Technology Telescope at the La Silla Observatory, in the Southern part of the Chilean Atacama Desert. The consortium is focussed on a clear scientific goal: the spectrograph will observe all kind of transient and variable sources discovered by different surveys with a highly flexible schedule, updated daily, based on the Target of Opportunity concept. It will provide a key spectroscopic partner to any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. SOXS will study a mixture of transients encompassing all distance scales and branches of astronomy, including fast alerts (such as gamma-ray bursts and gravitational waves), mid-term alerts (such as supernovae and X-ray transients), and fixed-time events (such as the close-by
Even if great progress has been done in tracing and modeling the galaxy spheroids formation and e... more Even if great progress has been done in tracing and modeling the galaxy spheroids formation and evolution, this topic still defied a general accepted explanation. Currently, the favorite models to explain the formation and evolution for galaxies are hierarchical merging and monolithic collapse. A way to discriminate between the above scenarios is to observe very deep in our nearby universe, to understand what kind of signature the stellar population has inherited from the galaxy formation mechanism. In order to investigate this aspect we presented an extensive project aimed at studying the stellar population of bulges in spiral galaxies to understand their chemical properties and whether these properties differ from those of elliptical galaxies. To achieve these goals, we observed a sample of disk galaxies in field and in cluster. We measured the main Lick indices (H_{beta}, Mg_2, , MgFe) and the principal kinematical parameters (velocity, velocity dispersion h_3 and h_4) as function of the galactocentric radius, in order to determine the age, metallicity and alpha-enhancement for all the sample galaxies. We do not find clear gradient in the alpha/Fe profiles. The constant and supersolar ( alpha/Fe = 0.3) values of the alpha-enhancement ratio along radius suggests that the formation of the bulk of the stars in spiral bulges occurred with the same short (less than 1 Gyr) timescale as found in elliptical and S0 galaxies. Therefore the alpha/Fe radial profiles, disfavor strong inside-out or outside-in scenarios and are in conflict with the pure monolithic collapse, where a positive gradient in the alpha-enhancement is expected. On the other hand the globally alpha/Fe enhanced stellar population is not expected in the hierarchical merging scenario where the star formation is triggered by the merger event and could give higher central values of alpha/Fe which decrease outwards.
The Messenger, 2020
The La Silla Observing Summer School was originally conceived with the goal of providing hands-on... more The La Silla Observing Summer School was originally conceived with the goal of providing hands-on training in the use of telescopes and astronomical instruments for senior masters and young doctoral students. The third La Silla Summer School ran over two weeks and was hosted by ESO's Office for Science and the La Silla Observatory. Twenty PhD and MSc students from several countries participated. They attended lectures on various observing modes and instrumentation but also on scientific presentations, time management, effective proposal writing, and career choices. For the hands-on part at the observatory, the students were supervised by seven ESO tutors. Four small research projects were offered, using three telescopes and four instruments. The students in each research group went through the full process of defining and discussing the observing strategies, conducting the observations, reducing and analysing the data and finally presenting the results to the scientific community at the ESO Vitacura offices. The next school is foreseen for the southern summer break of 2022.
This paper presents the results of the redshift survey of 138 candidate compact groups from the D... more This paper presents the results of the redshift survey of 138 candidate compact groups from the DPOSS II catalog (Iovino et al., 2003; de Carvalho et al. 2005), which extends the available redshift range of spectroscopically confirmed compact groups of galaxies to z ∼ 0.2. The aims of the survey are to confirm group membership via spectroscopic redshift information, to measure the characteristic parameters of the confirmed groups, namely mass, radius, luminosity, velocity dispersion and crossing time, and to compare them with those of nearby compact groups. Using available information from the literature, we also studied the surrounding group environment and searched for additional, previously unknown, group members, or larger scale structures to whom the group might be associated. Of the 138 observed groups, 96 had three or more concordant galaxies, i.e. a 70% success rate. Of these 96, 62 are isolated on the sky, while the other 34 are close on the sky to a larger scale structure. The remaining objects turned out to be couple of pairs or chance projection of galaxies on the sky. The median redshift of all the confirmed groups is z ∼ 0.12, to be compared with a median redshift of 0.03 for the local sample of compact groups by Hickson. The average group radius is 50 Kpc, the median radial velocity dispersion is 313km s −1 , while typical crossing times range from 0.002 H −1 0 to 0.135 H −1 0 with a median value of 0.02 H −1 0 , which is quite similar to the values measured for the Hickson's compact groups sample. The average mass-to-light ratio for the whole sample, M/L B , is 296, which is significantly higher than the value measured for Hickson's compact groups, while the median mass, measured using the virial theorem, is M = 2.9× 10 13 M. The values quoted above change downward and closely resemble the average values measured for Hickson's compact groups if we select only the groups which are isolated on the sky. We also found that the characteristics of the groups do depend on their environment. We conclude that we observe a population of compact groups very similar to those observed at zero redshift. Furthermore, a careful selection of the environment surrounding compact groups is necessary in order to detect truly isolated compact structures.
The Messenger, Jun 1, 2001
Near-infrared observations of the spiral pattern in galaxies reveal the underlying density pertur... more Near-infrared observations of the spiral pattern in galaxies reveal the underlying density perturbations in the disks much better than maps in visual bands although some population effects are still present. A preliminary analysis of the spiral structure in 53 nearby spiral galaxies observed in the K band with SOFI/NTT is presented including the distribution of arm amplitudes and pitch angles. The frequency of bars in a subsample of 30 galaxies classified as non-barred in the visual was studied. In the K band, ~75% of these galaxies showed bars or oval distortions with a relative amplitude larger than 2% and a length in excess of 5 arcsec. This suggests that the majority (i.e. ~95%) of all spirals may have some kind of bar perturbation although in many cases weak. The histogram of relative bar amplitudes suggested a bi-modal distribution. Most galaxies observed in K have a grand design, two-armed, symmetric spiral pattern in their inner parts which often breakup into tighter winded,...
A sample of 54 nearby spiral galaxies was observed in the K' band with 3.5m NTT telescope, La... more A sample of 54 nearby spiral galaxies was observed in the K' band with 3.5m NTT telescope, La Silla, ESO, to study the morphology and other properties of spiral perturbations in their disks. A subsample of the galaxies classified as ordinary, non-barred spirals was used to estimate frequency of weak bars detectable in the K' band. The tables provide general structural properties of the galaxies including estimated of the bulge/disk decomposition and spiral perturbations in the disks. (2 data files).
We present observations in the optical, near-infrared and millimetre of the Ultraluminous Infrare... more We present observations in the optical, near-infrared and millimetre of the Ultraluminous Infrared Galaxy IRAS 19254-7245, also known as The Superantennae. The galaxy is an interacting system with a double nucleus and long tails extending for about 350 Kpc. We study in details the southern component of the system which is optically classified as a Sy2 galaxy.
Multi-wavelength observations of Hickson's Compact Groups (HCGs) have shown that many of thes... more Multi-wavelength observations of Hickson's Compact Groups (HCGs) have shown that many of these groups are physical bound structures and are in different stage of evolution, from spiral-dominated systems to almost merged objects. Very few studies have analysed the Southern Compact Groups (SCGs) sample, which is thought to be younger that HCGs, due to an on average higher number of spiral galaxies. We present here the first results from optical and radio observations on a pilot sample of SCGs. Optical observations of SCGs obtained with ESO telescopes and radio data from the ATCA allow us to probe the distribution of the warm intra-group medium and the evolutionary stage of each group, by means of morphological studies and via measurements of star formation and other types of nuclear activity. (3 data files).
All the data were obtained with the 3.58m New Technology Telescope (NTT) and the ESO Multi Mode I... more All the data were obtained with the 3.58m New Technology Telescope (NTT) and the ESO Multi Mode Instrument (EMMI). (2 data files).
We have conducted two surveys of compact groups of galaxies in the Southern hemisphere, one at z ... more We have conducted two surveys of compact groups of galaxies in the Southern hemisphere, one at z ≤ 0.03 and another at 0.05 ≤ z ≤ 0.2, with the aim of studying the evolution of the group member galaxies and the groups themselves. Most of the observed targets are physically bound structures with a high density on the sky and a crossing time τ ≤ 1 Gyr. We conclude that either compact groups are stabilized somehow by their dark matter halo or that we observed two distinct generations of compact groups.
During astronomical observations it has always been of great importance to be able to asses the q... more During astronomical observations it has always been of great importance to be able to asses the quality of the data being collected at the telescope and the conditions of the night. The way astronomers normally do this is by processing the raw data transmitted from the instrument workstation with some semiautomated software package. The data reduction normally depends on the instrument characteristics, but basically the main divisions are set by the wavelength range covered (optical, infrared, sub-millimetric, radio) and by the way the light is collected (imaging or spectroscopy).
ESO Astrophysics Symposia European Southern Observatory
Photometric calibration observations are routinely carried out with all ESO imaging cameras in ev... more Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently, we have started the FORS Absolute Photometry Project (FAP) to investigate, if and how percent-level absolute photometric accuracy can be achieved with FORS1, and how such photometric calibration can be offered to observers. We found that there are significant differences between the sky-flats and the true photometric response of the instrument which partially depend on the rotator angle. A second order correction to the skyflat significantly improves the relative photometry within the field. We demonstrate the feasibility of percent level photometry and describe the calibrations necessary to achieve that level of accuracy.
Ground-based and Airborne Instrumentation for Astronomy IX
SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage... more SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage from U-to H-band, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory. It is designed to observe all kind of transients and variable sources discovered by different surveys with a highly flexible schedule maintained by the consortium, based on the Target of Opportunity concept. SOXS is going to be a fundamental spectroscopic partner for any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. This paper gives an updated status of the project, when the instrument is in the advanced phase of integration and testing in Europe, prior to the activities in Chile.
Summary. The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust whi... more Summary. The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2 1 to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud. 1
Ground-based and Airborne Instrumentation for Astronomy VIII, 2020
SOXS (Son Of X-Shooter) is a single object spectrograph, characterized by offering a wide simulta... more SOXS (Son Of X-Shooter) is a single object spectrograph, characterized by offering a wide simultaneous spectral coverage from U-to H-band, built by an international consortium for the 3.6-m ESO New Technology Telescope at the La Silla Observatory, in the Southern part of the Chilean Atacama Desert. The consortium is focussed on a clear scientific goal: the spectrograph will observe all kind of transient and variable sources discovered by different surveys with a highly flexible schedule, updated daily, based on the Target of Opportunity concept. It will provide a key spectroscopic partner to any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. SOXS will study a mixture of transients encompassing all distance scales and branches of astronomy, including fast alerts (such as gamma-ray bursts and gravitational waves), mid-term alerts (such as supernovae and X-ray transients), and fixed-time events (such as the close-by
Even if great progress has been done in tracing and modeling the galaxy spheroids formation and e... more Even if great progress has been done in tracing and modeling the galaxy spheroids formation and evolution, this topic still defied a general accepted explanation. Currently, the favorite models to explain the formation and evolution for galaxies are hierarchical merging and monolithic collapse. A way to discriminate between the above scenarios is to observe very deep in our nearby universe, to understand what kind of signature the stellar population has inherited from the galaxy formation mechanism. In order to investigate this aspect we presented an extensive project aimed at studying the stellar population of bulges in spiral galaxies to understand their chemical properties and whether these properties differ from those of elliptical galaxies. To achieve these goals, we observed a sample of disk galaxies in field and in cluster. We measured the main Lick indices (H_{beta}, Mg_2, , MgFe) and the principal kinematical parameters (velocity, velocity dispersion h_3 and h_4) as function of the galactocentric radius, in order to determine the age, metallicity and alpha-enhancement for all the sample galaxies. We do not find clear gradient in the alpha/Fe profiles. The constant and supersolar ( alpha/Fe = 0.3) values of the alpha-enhancement ratio along radius suggests that the formation of the bulk of the stars in spiral bulges occurred with the same short (less than 1 Gyr) timescale as found in elliptical and S0 galaxies. Therefore the alpha/Fe radial profiles, disfavor strong inside-out or outside-in scenarios and are in conflict with the pure monolithic collapse, where a positive gradient in the alpha-enhancement is expected. On the other hand the globally alpha/Fe enhanced stellar population is not expected in the hierarchical merging scenario where the star formation is triggered by the merger event and could give higher central values of alpha/Fe which decrease outwards.
The Messenger, 2020
The La Silla Observing Summer School was originally conceived with the goal of providing hands-on... more The La Silla Observing Summer School was originally conceived with the goal of providing hands-on training in the use of telescopes and astronomical instruments for senior masters and young doctoral students. The third La Silla Summer School ran over two weeks and was hosted by ESO's Office for Science and the La Silla Observatory. Twenty PhD and MSc students from several countries participated. They attended lectures on various observing modes and instrumentation but also on scientific presentations, time management, effective proposal writing, and career choices. For the hands-on part at the observatory, the students were supervised by seven ESO tutors. Four small research projects were offered, using three telescopes and four instruments. The students in each research group went through the full process of defining and discussing the observing strategies, conducting the observations, reducing and analysing the data and finally presenting the results to the scientific community at the ESO Vitacura offices. The next school is foreseen for the southern summer break of 2022.
This paper presents the results of the redshift survey of 138 candidate compact groups from the D... more This paper presents the results of the redshift survey of 138 candidate compact groups from the DPOSS II catalog (Iovino et al., 2003; de Carvalho et al. 2005), which extends the available redshift range of spectroscopically confirmed compact groups of galaxies to z ∼ 0.2. The aims of the survey are to confirm group membership via spectroscopic redshift information, to measure the characteristic parameters of the confirmed groups, namely mass, radius, luminosity, velocity dispersion and crossing time, and to compare them with those of nearby compact groups. Using available information from the literature, we also studied the surrounding group environment and searched for additional, previously unknown, group members, or larger scale structures to whom the group might be associated. Of the 138 observed groups, 96 had three or more concordant galaxies, i.e. a 70% success rate. Of these 96, 62 are isolated on the sky, while the other 34 are close on the sky to a larger scale structure. The remaining objects turned out to be couple of pairs or chance projection of galaxies on the sky. The median redshift of all the confirmed groups is z ∼ 0.12, to be compared with a median redshift of 0.03 for the local sample of compact groups by Hickson. The average group radius is 50 Kpc, the median radial velocity dispersion is 313km s −1 , while typical crossing times range from 0.002 H −1 0 to 0.135 H −1 0 with a median value of 0.02 H −1 0 , which is quite similar to the values measured for the Hickson's compact groups sample. The average mass-to-light ratio for the whole sample, M/L B , is 296, which is significantly higher than the value measured for Hickson's compact groups, while the median mass, measured using the virial theorem, is M = 2.9× 10 13 M. The values quoted above change downward and closely resemble the average values measured for Hickson's compact groups if we select only the groups which are isolated on the sky. We also found that the characteristics of the groups do depend on their environment. We conclude that we observe a population of compact groups very similar to those observed at zero redshift. Furthermore, a careful selection of the environment surrounding compact groups is necessary in order to detect truly isolated compact structures.
The Messenger, Jun 1, 2001
Near-infrared observations of the spiral pattern in galaxies reveal the underlying density pertur... more Near-infrared observations of the spiral pattern in galaxies reveal the underlying density perturbations in the disks much better than maps in visual bands although some population effects are still present. A preliminary analysis of the spiral structure in 53 nearby spiral galaxies observed in the K band with SOFI/NTT is presented including the distribution of arm amplitudes and pitch angles. The frequency of bars in a subsample of 30 galaxies classified as non-barred in the visual was studied. In the K band, ~75% of these galaxies showed bars or oval distortions with a relative amplitude larger than 2% and a length in excess of 5 arcsec. This suggests that the majority (i.e. ~95%) of all spirals may have some kind of bar perturbation although in many cases weak. The histogram of relative bar amplitudes suggested a bi-modal distribution. Most galaxies observed in K have a grand design, two-armed, symmetric spiral pattern in their inner parts which often breakup into tighter winded,...
A sample of 54 nearby spiral galaxies was observed in the K' band with 3.5m NTT telescope, La... more A sample of 54 nearby spiral galaxies was observed in the K' band with 3.5m NTT telescope, La Silla, ESO, to study the morphology and other properties of spiral perturbations in their disks. A subsample of the galaxies classified as ordinary, non-barred spirals was used to estimate frequency of weak bars detectable in the K' band. The tables provide general structural properties of the galaxies including estimated of the bulge/disk decomposition and spiral perturbations in the disks. (2 data files).
We present observations in the optical, near-infrared and millimetre of the Ultraluminous Infrare... more We present observations in the optical, near-infrared and millimetre of the Ultraluminous Infrared Galaxy IRAS 19254-7245, also known as The Superantennae. The galaxy is an interacting system with a double nucleus and long tails extending for about 350 Kpc. We study in details the southern component of the system which is optically classified as a Sy2 galaxy.
Multi-wavelength observations of Hickson's Compact Groups (HCGs) have shown that many of thes... more Multi-wavelength observations of Hickson's Compact Groups (HCGs) have shown that many of these groups are physical bound structures and are in different stage of evolution, from spiral-dominated systems to almost merged objects. Very few studies have analysed the Southern Compact Groups (SCGs) sample, which is thought to be younger that HCGs, due to an on average higher number of spiral galaxies. We present here the first results from optical and radio observations on a pilot sample of SCGs. Optical observations of SCGs obtained with ESO telescopes and radio data from the ATCA allow us to probe the distribution of the warm intra-group medium and the evolutionary stage of each group, by means of morphological studies and via measurements of star formation and other types of nuclear activity. (3 data files).
All the data were obtained with the 3.58m New Technology Telescope (NTT) and the ESO Multi Mode I... more All the data were obtained with the 3.58m New Technology Telescope (NTT) and the ESO Multi Mode Instrument (EMMI). (2 data files).
We have conducted two surveys of compact groups of galaxies in the Southern hemisphere, one at z ... more We have conducted two surveys of compact groups of galaxies in the Southern hemisphere, one at z ≤ 0.03 and another at 0.05 ≤ z ≤ 0.2, with the aim of studying the evolution of the group member galaxies and the groups themselves. Most of the observed targets are physically bound structures with a high density on the sky and a crossing time τ ≤ 1 Gyr. We conclude that either compact groups are stabilized somehow by their dark matter halo or that we observed two distinct generations of compact groups.
During astronomical observations it has always been of great importance to be able to asses the q... more During astronomical observations it has always been of great importance to be able to asses the quality of the data being collected at the telescope and the conditions of the night. The way astronomers normally do this is by processing the raw data transmitted from the instrument workstation with some semiautomated software package. The data reduction normally depends on the instrument characteristics, but basically the main divisions are set by the wavelength range covered (optical, infrared, sub-millimetric, radio) and by the way the light is collected (imaging or spectroscopy).
ESO Astrophysics Symposia European Southern Observatory
Photometric calibration observations are routinely carried out with all ESO imaging cameras in ev... more Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently, we have started the FORS Absolute Photometry Project (FAP) to investigate, if and how percent-level absolute photometric accuracy can be achieved with FORS1, and how such photometric calibration can be offered to observers. We found that there are significant differences between the sky-flats and the true photometric response of the instrument which partially depend on the rotator angle. A second order correction to the skyflat significantly improves the relative photometry within the field. We demonstrate the feasibility of percent level photometry and describe the calibrations necessary to achieve that level of accuracy.