- ID:
- ivo://CDS.VizieR/J/A+A/607/A110
- Title:
- CO properties of compact group galaxies
- Short Name:
- J/A+A/607/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compact groups (CGs) provide an environment in which interactions between galaxies and with the intra-group medium enable and accelerate galaxy transitions from actively star forming to quiescent. Galaxies in transition from active to quiescent can be selected, by their infrared (IR) colors, as canyon or infrared transition zone (IRTZ) galaxies. We used a sample of CG galaxies with IR data from the Wide Field Infrared Survey Explorer (WISE) allowing us to calculate the stellar mass and star formation rate (SFR) for each galaxy. Furthermore, we present new CO(1-0) data for 27 galaxies and collect data from the literature to calculate the molecular gas mass for a total sample of 130 galaxies. This data set allows us to study the difference in the molecular gas fraction (Mmol/Mstar) and star formation efficiency (SFE=SFR/Mmol) between active, quiescent, and transitioning (i.e., canyon and IRTZ) galaxies. We find that transitioning galaxies have a mean molecular gas fraction and a mean SFE that are significantly lower than those of actively star-forming galaxies. The molecular gas fraction is higher than that of quiescent galaxies, whereas the SFE is similar. These results indicate that the transition from actively star-forming to quiescent in CG galaxies goes along with a loss of molecular gas, possibly due to tidal forces exerted from the neighboring galaxies or a decrease in the gas density. In addition, the remaining molecular gas loses its ability to form stars efficiently, possibly owing to turbulence perturbing the gas, as seen in other, well-studied examples such as Stephan's Quintet and HCG 57. Thus, the amount and properties of molecular gas play a crucial role in the environmentally driven transition of galaxies from actively star forming to quiescent.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/1071
- Title:
- Cores in IR Dark Clouds for 300<=l<=330
- Short Name:
- J/MNRAS/422/1071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used data taken as part of the Herschel infrared Galactic Plane survey (Hi-GAL) to study 3171 infrared dark cloud (IRDC) candidates that were identified in the mid-IR (8um) by Spitzer (we refer to these as 'Spitzer-dark' regions). They all lie in the range l=300-330{deg} and |b|<=1{deg}. Of these, only 1205 were seen in emission in the far-IR (250-500um) by Herschel (we call these 'Herschel-bright' clouds). It is predicted that a dense cloud will not only be seen in absorption in the mid-IR, but will also be seen in emission in the far-IR at the longest Herschel wavebands (250-500um). If a region is dark at all wavelengths throughout the mid-IR and far-IR, then it is most likely to be simply a region of lower background IR emission (a 'hole in the sky'). Hence, it appears that previous surveys, based on Spitzer and other mid-IR data alone, may have overestimated the total IRDC population by a factor of ~2. This has implications for estimates of the star formation rate in IRDCs in the Galaxy. We studied the 1205 Herschel-bright IRDCs at 250um and found that 972 of them had at least one clearly defined 250-um peak, indicating that they contained one or more dense cores. Of these, 653 (67 per cent) contained an 8-um point source somewhere within the cloud, 149 (15 per cent) contained a 24-um point source but no 8-um source and 170 (18 per cent) contained no 24- or 8-um point sources. We use these statistics to make inferences about the lifetimes of the various evolutionary stages of IRDCs.
183. COSMOS 70um sources
- ID:
- ivo://CDS.VizieR/J/ApJ/709/572
- Title:
- COSMOS 70um sources
- Short Name:
- J/ApJ/709/572
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large robust sample of 1503 reliable and unconfused 70um selected sources from the multiwavelength data set of the Cosmic Evolution Survey. Using the Spitzer IRAC and MIPS photometry, we estimate the total infrared (IR) luminosity, LIR (8-1000um), by finding the best-fit template from several different template libraries. The long-wavelength 70 and 160um data allow us to obtain a reliable estimate of LIR, accurate to within 0.2 and 0.05dex, respectively. The 70um data point enables a significant improvement over the luminosity estimates possible with only a 24um detection. The full sample spans a wide range in IR luminosity, LIR~10^8^-10^14^L_{sun}_, with a median luminosity of 10^11.4^L_{sun}_. We identify a total of 687 luminous, 303 ultraluminous, and 31 hyperluminous infrared galaxies (LIRGs, ULIRGs, and HyLIRGs) over the redshift range 0.01<z<3.5 with a median redshift of 0.5. Presented here are the full spectral energy distributions (SEDs) for each of the sources compiled from the extensive multiwavelength data set from the ultraviolet (UV) to the far-infrared. A catalog of the general properties of the sample (including the photometry, redshifts, and LIR) is included with this paper.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/3445
- Title:
- Covering factor of warm dust in quasars
- Short Name:
- J/MNRAS/430/3445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By combining newly obtained infrared photometric data from the All-Sky Data Release of the Wide-field Infrared Survey Explorer with spectroscopic data from the Seventh Data Release of the Sloan Digital Sky Survey, we study the covering factor of warm dust (CFWD) for a large quasar sample, as well as the relations between CFWD and other physical parameters of quasars. We find a strong correlation between the flux ratio in the mid-infrared to near-ultraviolet and the slope of the near-ultraviolet spectra, which is interpreted as a dust extinction effect. After correcting for dust extinction utilizing the above correlation, we examine the relations between CFWD and active galactic nucleus properties: bolometric luminosity (L_bol_), black hole mass (M_BH_) and Eddington ratio (L/L_Edd_). We confirm the anticorrelation between CFWD and L_bol_. Further, we find that CFWD is anticorrelated with M_BH_ but is independent of L/L_Edd_. Radio-loud quasars are found to follow the same correlations as radio-quiet quasars. Monte Carlo simulations show that the anisotropy of the UV-optical continuum of the accretion disc can have a significant effect, but is not likely to dominate the CFWD-L_bol_ correlation.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A192
- Title:
- C3R2-KMOS zsp & galaxy physical properties
- Short Name:
- J/A+A/642/A192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Complete Calibration of the Colour-Redshift Relation survey (C3R2) is a spectroscopic effort involving ESO and Keck facilities designed specifically to empirically calibrate the galaxy colour-redshift relation - P(zjC) to the Euclid depth (i_AB_=24.5) and is intimately linked to the success of upcoming Stage IV dark energy missions based on weak lensing cosmology. The aim is to build a spectroscopic calibration sample that is as representative as possible of the galaxies of the Euclid weak lensing sample. In order to minimise the number of spectroscopic observations necessary to fill the gaps in current knowledge of the P(zjC), self-organising map (SOM) representations of the galaxy colour space have been constructed. Here we present the first results of an ESO@VLT Large Programme approved in the context of C3R2, which makes use of the two VLT optical and near-infrared multi-object spectrographs, FORS2 and KMOS. This data release paper focuses on high-quality spectroscopic redshifts of high-redshift galaxies observed with the KMOS spectrograph in the near-infrared H- and K-bands. A total of 424 highly-reliable redshifts are measured in the 1.3<=z<=2.5 range, with total success rates of 60.7% in the H-band and 32.8% in the K-band. The newly determined redshifts fill 55% of high (mainly regions with no spectroscopic measurements) and 35% of lower (regions with low-resolution/low-quality spectroscopic measurements) priority empty SOMgrid cells.We measured H fluxes in a 1.2" radius aperture from the spectra of the spectroscopically confirmed galaxies and converted them into star formation rates. In addition, we performed an SED fitting analysis on the same sample in order to derive stellar masses, E(B-V), total magnitudes, and SFRs. We combine the results obtained from the spectra with those derived via SED fitting, and we show that the spectroscopic failures come from either weakly star-forming galaxies (at z<1.7, i.e. in the H-band) or low S/N spectra (in the K-band) of z>2 galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/417/1210
- Title:
- DA-white dwarfs from SDSS and UKIDSS
- Short Name:
- J/MNRAS/417/1210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a method which uses colour-colour cuts on the Sloan Digital Sky Survey (SDSS) photometry to select white dwarfs with hydrogen-rich (DA) atmospheres without the recourse to spectroscopy. This method results in a sample of DA white dwarfs that is 95 per cent complete at an efficiency of returning a true DA white dwarf of 62 per cent. The approach was applied to SDSS Data Release 7 for objects with and without SDSS spectroscopy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/487/3162
- Title:
- Debris disc stars metallicity & Li properties
- Short Name:
- J/MNRAS/487/3162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf stars with debris discs and planets appear to be excellent laboratories to study the core accretion theory of planets formation. These systems are however, insufficiently studied. In this paper we present the main metallicity and lithium abundance properties of these stars together with stars with only debris discs and stars with only planets. Stars without detected planets nor discs are also considered. The analysed sample is formed by main-sequence FGK field single stars. Apart from the basic stellar parameters, we include the use of dusty discs masses. The main results show for the first time that the dust mass of debris disc stars with planets correlate with metallicity. We confirm that these disc dust masses are related to their central stellar masses. Separately, the masses of stars and those of planets also correlate with metallicity. We conclude that two conditions are necessary to form giant planets: to have a sufficient metallicity and also a sufficient protoplanetary mass of gas and dust. The debris discs masses of stars without giant planets do not correlate with metallicity, because they do not fulfil these two conditions. Concerning lithium, by adopting a stellar model for lithium depletion based on a strong interaction between the star and a protoplanetary disc, we found that in agreement with the model predictions, observations indicate that the main lithium depletion occurs during this initial protoplanetary evolution stage. We show that the ultimately lithium depletion is independent of the presence or absence of planets and appears to be only age dependent.
- ID:
- ivo://CDS.VizieR/J/AJ/148/3
- Title:
- Debris disk candidates detected with AKARI/FIS
- Short Name:
- J/AJ/148/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We cross-correlate the Hipparcos main-sequence star catalog with the AKARI/FIS catalog and identify 136 stars (at >90% reliability) with far-infrared detections in at least one band. After rejecting 57 stars classified as young stellar objects, Be stars and other type stars with known dust disks or with potential contaminations, and 4 stars without infrared excess emission, we obtain a sample of 75 candidate stars with debris disks. Stars in our sample cover spectral types from B to K with most being early types. This represents a unique sample of luminous debris disks that derived uniformly from an all-sky survey with a spatial resolution factor of four better than the previous such survey by IRAS. Moreover, by collecting the infrared photometric data from other public archives, almost three-quarters of them have infrared excesses in more than one band, allowing an estimate of the dust temperatures. We fit the blackbody model to the broadband spectral energy distribution of these stars to derive the statistical distribution of the disk parameters. Four B stars with excesses in four or more bands require a double blackbody model, with the high one around 100 or 200K and the low one around 40-50K.
- ID:
- ivo://CDS.VizieR/J/ApJ/636/1098
- Title:
- Debris disks around solar-type stars
- Short Name:
- J/ApJ/636/1098
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have searched for infrared excesses around a well-defined sample of 69 FGK main-sequence field stars. These stars were selected without regard to their age, metallicity, or any previous detection of IR excess; they have a median age of 4Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3721
- Title:
- Deep ALMA photometry of distant X-ray AGN
- Short Name:
- J/MNRAS/478/3721
- Date:
- 10 Dec 2021 00:23:44
- Publisher:
- CDS
- Description:
- We present the star formation rates (SFRs) of a sample of 109 galaxies with X-ray-selected active galactic nuclei (AGNs) with moderate to high X-ray luminosities (L_2-8keV_=10^42^-10^45^erg/s), at redshifts 1<z<4.7, that were selected to be faint or undetected in the Herschel bands. We combine our deep Atacama large (sub-)millimetre array (ALMA) continuum observations with deblended 8-500um photometry from Spitzer and Herschel, and use infrared (IR) spectral energy distribution (SED) fitting and AGN - star formation decomposition methods. The addition of the ALMA photometry results in an order of magnitude more X-ray AGN in our sample with a measured SFR (now 37%). The remaining 63 % of the sources have SFR upper limits that are typically a factor of 2-10 times lower than the pre-ALMA constraints. With the improved constraints on the IR SEDs, we can now identify a mid-IR (MIR) AGN component in 50% of our sample, compared to only ~1% previously. We further explore the F_870um_/F_24um_ -redshift plane as a tool for the identification of MIR-emitting AGN, for three different samples representing AGN-dominated, star formation-dominated, and composite sources. We demonstrate that the F_870um_/F_24um_ -redshift plane can successfully split between AGN and star formation-dominated sources, and can be used as an AGN identification method.
