- ID:
- ivo://CDS.VizieR/J/ApJ/879/131
- Title:
- UV-FIR obs. of post-starburst galaxies & dust masses
- Short Name:
- J/ApJ/879/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive dust masses (M_dust_) from the spectral energy distributions of 58 post-starburst galaxies (PSBs). There is an anticorrelation between specific dust mass (M_dust_/M_*_) and the time elapsed since the starburst ended, indicating that dust was either destroyed, expelled, or rendered undetectable over the ~1Gyr after the burst. The M_dust_/M_*_ depletion timescale, 205_-37_^+58^Myr, is consistent with that of the CO-traced M_H2_/M_*_, suggesting that dust and gas are altered via the same process. Extrapolating these trends leads to the M_dust_/M_*_ and M_H2_/M_*_ values of early-type galaxies (ETGs) within 1-2Gyr, a timescale consistent with the evolution of other PSB properties into ETGs. Comparing Mdust and M_H2_ for PSBs yields a calibration, log M_H2_=0.45logM_dust_+6.02, that allows us to place 33 PSBs on the Kennicutt-Schmidt (KS) plane, {Sigma}SFR-{Sigma}M_H2_. Over the first ~200-300Myr, the PSBs evolve down and off of the KS relation, as their star formation rate (SFR) decreases more rapidly than M_H2_. Afterwards, M_H2_ continues to decline whereas the SFR levels off. These trends suggest that the star formation efficiency bottoms out at 10^-11^/yr and will rise to ETG levels within 0.5-1.1Gyr afterwards. The SFR decline after the burst is likely due to the absence of gas denser than the CO-traced H2. The mechanism of the M_dust_/M_*_ and M_H2_/M_*_ decline, whose timescale suggests active galactic nucleus/low-ionization nuclear emission-line region feedback, may also be preventing the large CO-traced molecular gas reservoirs from collapsing and forming denser star-forming clouds.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/771/13
- Title:
- UV-IR photometry of SMC stars
- Short Name:
- J/ApJ/771/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nature of the progenitors of Type Ia supernovae (SNe Ia) is still a mystery. While plausible candidates are known for both the single-degenerate and double-degenerate models, the observed numbers fall significantly short of what is required to reproduce the SNe Ia rate. Some of the most promising single-degenerate Type Ia progenitors are recurrent novae and super-soft sources (SSS). White dwarfs (WDs) with higher mass transfer rates can also be SN Ia progenitors. For these rapidly accreting white dwarfs (RAWDs), more material than is needed for steady burning accretes on the WD, and extends the WD's photosphere. Unlike SSS, such objects will likely not be detectable at soft X-ray energies, but will be bright at longer wavelengths, such as the far-ultraviolet (UV). Possible examples include LMC N66 and the V Sagittae stars. We present a survey using multi-object spectrographs looking for RAWDs in the central core of the Small Magellanic Cloud (SMC), from objects selected to be bright in the far-UV and with blue far UV-V colors. While we find some unusual objects, and recover known planetary nebula and Wolf-Rayet (WR) stars, we detect no candidate RAWD. The upper limits from this non-detection depend on our expectations of what an RAWD should look like, as well assumptions about the internal extinction of the SMC. Assuming they resemble LMC N66 or fainter versions of WR stars we set an upper limit of 10-14 RAWDs in the SMC. However, our survey is unlikely to detect objects like V Sge, and hence we cannot set meaningful upper limits if RAWDs generally resemble V Sge.
2603. UV photometry of M15
- ID:
- ivo://CDS.VizieR/J/ApJ/670/379
- Title:
- UV photometry of M15
- Short Name:
- J/ApJ/670/379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep FUV and NUV images of the inner region of the dense globular cluster M15 with the HST ACS. The FUV-NUV color-magnitude diagram shows a well-defined track of horizontal branch stars, as well as a trail of blue stragglers and white dwarfs. The main-sequence turnoff is clearly visible at FUV~22.5mag and FUV-NUV~3mag, and the main-sequence stars form a prominent track that extends at least 2mag below the main-sequence turnoff. As such, this is the deepest FUV-NUV color-magnitude diagram of a globular cluster presented so far. Cataclysmic variable and blue straggler candidates are the most centrally concentrated stellar populations, which might either be an effect of mass segregation or reflect the preferred birthplace in the dense cluster core of such dynamically formed objects. We find 41 FUV sources that exhibit significant variability. We classify the variables based on an analysis of their UV colors and variability properties. We find four previously known RR Lyrae and 13 further RR Lyrae candidates, one known Cepheid and six further candidates, six cataclysmic variable candidates, one known and one probable SX Phoenicis star, and the well-known low-mass X-ray binary AC 211. Our analysis represents the first detection of SX Phoenicis pulsations in the FUV. We find that Cepheids, RR Lyrae stars, and SX Phoenicis exhibit massive variability amplitudes in this wave band (several magnitudes).
- ID:
- ivo://CDS.VizieR/J/A+A/545/A141
- Title:
- UV selected sources in the GOODS-S field
- Short Name:
- J/A+A/545/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust attenuation in galaxies is poorly known, especially at high redshift. And yet the amount of dust attenuation is a key parameter to deduce accurate star formation rates from ultraviolet (UV) rest-frame measurements. The wavelength dependence of the dust attenuation is also of fundamental importance to interpret the observed spectral energy distributions (SEDs) and to derive photometric redshifts or physical properties of galaxies. We want to study dust attenuation at UV wavelengths at high redshift, where the UV is redshifted to the observed visible light wavelength range. In particular, we search for a UV bump and related implications for dust attenuation determinations.
- ID:
- ivo://CDS.VizieR/J/AJ/139/1338
- Title:
- UV-selected stars in Tau and Upper Sco
- Short Name:
- J/AJ/139/1338
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a Galaxy Evolution Explorer (GALEX) Cycle 1 guest investigator program covering 56deg^2^ near the Taurus T association and 12deg^2^ along the northern edge of the Upper Scorpius OB association. We combined photometry in the GALEX far-ultraviolet and near-ultraviolet bands with data from the Two Micron All Sky Survey to identify candidate young (<~100Myr old) stars as those with an ultraviolet excess relative to older main-sequence stars. Follow-up spectroscopy of a partial sample of these candidates suggests five new members of Taurus, with 8-20 expected from additional observations, and five new members of Upper Scorpius, with three to six expected from additional observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/731/28
- Title:
- UV star-forming association in spiral galaxies
- Short Name:
- J/ApJ/731/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate recent star formation in the extended ultraviolet (XUV) disks of five nearby galaxies (NGC 0628, NGC 2090, NGC 2841, NGC 3621, and NGC 5055) using a long wavelength baseline comprised of ultraviolet and mid-infrared imaging from the Galaxy Evolution Explorer and the Spitzer Infrared Array Camera. We identify 229 unresolved stellar complexes across targeted portions of their XUV disks and utilize spectral energy distribution fitting to measure their stellar ages and masses through comparison with Starburst99 population synthesis models of instantaneous burst populations. We find that the median age of outer-disk associations in our sample is ~100Myr with a large dispersion that spans the entire range of our models (1Myr to 1Gyr). This relatively evolved state for most associations addresses the observed dearth of H{alpha} emission in some outer disks, as H{alpha} can only be observed in star-forming regions younger than ~10Myr. The large age dispersion is robust against variations in extinction (in the range E(B-V)=0-0.3mag) and variations in the upper end of the stellar initial mass function (IMF). In particular, we demonstrate that the age dispersion is insensitive to steepening of the IMF, up to extreme slopes.
- ID:
- ivo://CDS.VizieR/J/ApJ/648/987
- Title:
- UV through far-IR analysis of M81
- Short Name:
- J/ApJ/648/987
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The recent star formation (SF) in the early-type spiral galaxy M81 is characterized using imaging observations from the far-ultraviolet to the far-infrared. We compare these data with models of the stellar, gas, and dust emission for subgalactic regions.
- ID:
- ivo://CDS.VizieR/J/ApJS/199/22
- Title:
- UV to far-IR photometry of galaxies
- Short Name:
- J/ApJS/199/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present a sample of cluster galaxies devoted to study the environmental influence on the star formation activity. This sample of galaxies inhabits in clusters showing a rich variety in their characteristics and have been observed by the SDSS-DR6 down to M_B_~-18, and by the Galaxy Evolution Explorer AIS throughout sky regions corresponding to several megaparsecs. We assign the broadband and emission-line fluxes from ultraviolet to far-infrared to each galaxy performing an accurate spectral energy distribution for spectral fitting analysis. The clusters follow the general X-ray luminosity versus velocity dispersion trend of L_X_{propto}{sigma}^4.4^_c_.
- ID:
- ivo://CDS.VizieR/J/ApJS/143/377
- Title:
- UV-to-FIR magnitudes for 83 starburst galaxies
- Short Name:
- J/ApJS/143/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a database of UV-to-FIR data of 83 nearby starburst galaxies. The galaxies are selected based upon the availability of IUE data. We have recalibrated the IUE UV spectra for these galaxies by incorporating the most recent improvements. For 45 of these galaxies we use observations by Storchi-Bergmann et al. (1995ApJS...98..103S) and McQuade et al. (1995ApJS...97..331M) for the spectra in the optical range. The NIR data are from new observations obtained at the NASA/IRTF and the Mount Laguna Observatory, combined with the published results from observations at the Kitt Peak National Observatory. In addition, published calibrated ISO data are included to provide mid-IR flux densities for some of the galaxies. The optical-to-IR data are matched as closely as possible to the IUE large aperture. In conjunction with IRAS and ISO FIR flux densities, all these data form a set of observed spectral energy distributions (SEDs) of the nuclear regions of nearby starburst galaxies. The SEDs should be useful in studying star formation and dust/gas attenuation in galaxies. We also present the magnitudes in the standard BVRI and various HST/WFPC2 bandpasses synthesized from the UV and optical wavelength ranges of these SEDs. For some of the galaxies, the HST/WFPC2 magnitudes synthesized from the SEDs are checked with those directly measured from WFPC2 images to test the photometric errors of the optical data and their effective matching of apertures with the UV data. The implications of the new SEDs on the star formation rates and dust/gas attenuation are briefly discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/533/A142
- Title:
- UV-to-IR fluxes of Hickson compact groups
- Short Name:
- J/A+A/533/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive study on the impact of the environment of compact galaxy groups on the evolution of their members using a multi-wavelength analysis, from the UV to the infrared, for a sample of 32 Hickson compact groups (HCGs) containing 135 galaxies. Fitting the SEDs of all galaxies with the state-of-the-art model of da Cunha (2008MNRAS.388.1595D) we can accurately calculate their mass, SFR, and extinction, as well as estimate their infrared luminosity and dust content. We compare our findings with samples of field galaxies, early-stage interacting pairs, and cluster galaxies with similar data. We find that classifying the groups as dynamically "old" or "young", depending on whether or not at least one quarter of their members are early-type systems, is physical and consistent with past classifications of HCGs based on their atomic gas content. Dynamically "old" groups are more compact and display higher velocity dispersions than "young" groups. Late-type galaxies in dynamically "young" groups have specific star formation rates (sSFRs), NUV-r, and mid-infrared colors which are similar to those of field and early stage interacting pair spirals. Late-type galaxies in dynamically "old" groups have redder NUV-r colors, as they have likely experienced several tidal encounters in the past building up their stellar mass, and display lower sSFRs. We identify several late-type galaxies which have sSFRs and colors similar to those of elliptical galaxies, since they lost part of their gas due to numerous interactions with other group members. Also, 25% of the elliptical galaxies in these groups have bluer UV/optical colors than normal ellipticals in the field, probably due to star formation as they accreted gas from other galaxies of the group, or via merging of dwarf companions. Finally, our SED modeling suggests that in 13 groups, 10 of which are dynamically "old", there is diffuse cold dust in the intragroup medium. All this evidence point to an evolutionary scenario in which the effects of the group environment and the properties of the galaxy members are not instantaneous. Early on, the influence of close companions to group galaxies is similar to the one of galaxy pairs in the field. However, as the time progresses, the effects of tidal torques and minor merging, shape the morphology and star formation history of the group galaxies, leading to an increase of the fraction of early-type members and a rapid built up of the stellar mass in the remaining late-type galaxies.
