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651. CO and HI in interacting galaxies
ID:
ivo://CDS.VizieR/J/A+AS/126/3
Title:
CO and HI in interacting galaxies
Short Name:
J/A+AS/126/3
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using SEST, the Parkes antenna and the Australia Telescope Compact Array, we have made a survey of the ^12^CO(1-0) and HI emission of an optically-selected sample of =~60 southern interacting and merging galaxies. In this paper we present the data and determine global masses of neutral gas (in molecular and atomic form) for the observed galaxies. We have detected HI in 26 systems and found that these galaxies have less than 15% of their gas in molecular form.
652. COBE DIRBE IR photometry
ID:
ivo://CDS.VizieR/J/ApJ/500/554
Title:
COBE DIRBE IR photometry
Short Name:
J/ApJ/500/554
Date:
21 Oct 2021
Publisher:
CDS
Description:
A comparison of the COBE Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the IRAS Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 57 galaxies. In this paper, we present the photometric data for these galaxies and an analysis of the seven galaxies that were detected at {lambda}>100{mu}m. Estimates of the ratio of the mass of the cold dust (CD) component detected at T_d_=20-30K to a very cold dust (VCD) component with T_d_~10-15K suggest that between 2%-100% of the cirrus-like CD mass can also exist in many of these galaxies as VCD. In one galaxy, M33, the DIRBE photometry at 240{mu}m suggests as much as 26 times as much VCD may be present as compared to the cirrus-like component. Further submillimeter measurements of this galaxy are required to verify such a large population of VCD. We also present 10 galaxies that were detected in the sky region not previously surveyed by IRAS and that can be used to construct a flux-limited all-sky catalog of galaxies brighter than 1000Jy with a modest completeness limit of about 65%.
653. CO-CAVITY pilot survey. CO spectra
ID:
ivo://CDS.VizieR/J/A+A/658/A124
Title:
CO-CAVITY pilot survey. CO spectra
Short Name:
J/A+A/658/A124
Date:
22 Feb 2022
Publisher:
CDS
Description:
Voids are the most under-dense large-scale regions in the Universe. Galaxies inhabiting voids are one of the keys to understand the intrinsic processes of galaxy evolution, as external factors such as multiple galaxy mergers or a dense self-collapsing environment are negligible. We present the first molecular gas mass survey of void galaxies. We compare these new data, together with data for the atomic gas mass (MHI) and star formation rate (SFR) from the literature to those of galaxies in filaments and walls in order to better understand how molecular gas and star formation are related to the large-scale environment. We observed at the IRAM 30-m telescope the CO(1-0) and CO(2-1) emission of 20 void galaxies selected from the VoidGalaxy Survey (VGS), with a stellar mass range from 108.5to 1010.3M. We detected 15 objects in at least one CO line. We compare the molecular gas mass (MH2), the star formation efficiency (SFE=SFR/MH2), the atomic gas mass, the molecular-to-atomic gas-mass ratio, and the specific star formation rate (sSFR) of the void galaxies with two control samples of galaxies in filaments and walls,selected from xCOLD GASS and EDGE-CALIFA, for different stellar mass bins and taking the star formation activity into account. In general, we do not find any significant differences between void galaxies and the control sample. In particular, we do not find any evidence for a difference in the molecular gas mass or molecular gas mass fraction. Also for the other parameters (SFE,atomic gas mass, molecular-to-atomic gas mass ratio, and sSFR) we find similar (within the errors) mean values between void, and filament and wall galaxies when limiting the sample to star-forming galaxies. We find no evidence for an enhanced sSFR in void galaxies. Some tentative differences emerge when studying trends with stellar mass: The SFE of void galaxies might be lower than in filament and wall galaxies for low stellar masses, and there might be a trend of increasing deficiency in the HI content in void galaxies compared to galaxies in filaments and walls for higher stellar masses, accompanied by an increase in the molecular-to-atomic gas-mass ratio. However, all trends with stellar mass are based on a low number of galaxies and need to be confirmed for a larger sample. The results for the molecular gas mass for a sample of 20 voids galaxies allowed us, for the first time, to make a statistical comparison to galaxies in filaments and walls. We do not find any significant differences of the molecular gas properties and the SFE, but we note that a larger sample is necessary to confirm this and be sensitive to subtle trends.
654. CO, [CI] and [NII] lines from Herschel spectra
ID:
ivo://CDS.VizieR/J/ApJ/829/93
Title:
CO, [CI] and [NII] lines from Herschel spectra
Short Name:
J/ApJ/829/93
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of all CO (J=4-3 through J=13-12), [CI], and [NII] lines available from extragalactic spectra from the Herschel SPIRE Fourier Transform Spectrometer (FTS) archive combined with observations of the low-J CO lines from the literature and from the Arizona Radio Observatory. This work examines the relationships between L_FIR_, L'_CO_, and L_CO_/L_CO,1-0_. We also present a new method for estimating probability distribution functions from marginal signal-to-noise ratio Herschel FTS spectra, which takes into account the instrumental "ringing" and the resulting highly correlated nature of the spectra. The slopes of log(L_FIR_) versus log(L'_CO_) are linear for all mid- to high-J CO lines and slightly sublinear if restricted to (ultra)luminous infrared galaxies ((U)LIRGs). The mid- to high-J CO luminosity relative to CO J=1-0 increases with increasing L_FIR_, indicating higher excitement of the molecular gas, although these ratios do not exceed ~180. For a given bin in L_FIR_, the luminosities relative to CO J=1-0 remain relatively flat from J=6-5 through J=13-12, across three orders of magnitude of L_FIR_. A single component theoretical photodissociation region (PDR) model cannot match these flat SLED shapes, although combinations of PDR models with mechanical heating added qualitatively match the shapes, indicating the need for further comprehensive modeling of the excitation processes of warm molecular gas in nearby galaxies.
655. CO+[CI] emission in distant galaxies
ID:
ivo://CDS.VizieR/J/A+A/641/A155
Title:
CO+[CI] emission in distant galaxies
Short Name:
J/A+A/641/A155
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the detection of multiple carbon monoxide CO line transitions with ALMA in a few tens of infrared-selected galaxies on and above the main sequence at z=1.1-1.7. We reliably detected the emission of CO(5-4), CO(2-1), and CO(7-6)+[CI](2-1) in 50, 33, and 13 galaxies, respectively, and we complemented this information with available CO(4-3) and [CI](1-0) fluxes for part of the sample, and by modeling of the optical-to-millimeter spectral energy distribution. We retrieve a quasi-linear relation between LIR and CO(5-4) or CO(7-6) for main-sequence galaxies and starbursts, corroborating the hypothesis that these transitions can be used as star formation rate (SFR) tracers. We find the CO excitation to steadily increase as a function of the star formation efficiency (SFE), the mean intensity of the radiation field warming the dust (<U>), the surface density of SFR (SigmaSFR), and, less distinctly, with the distance from the main sequence. This adds to the tentative evidence for higher excitation of the CO+[CI] spectral line energy distribution (SLED) of starburst galaxies relative to that for main-sequence objects, where the dust opacities play a minor role in shaping the high-J CO transitions in our sample. However, the distinction between the average SLED of upper main-sequence and starburst galaxies is blurred, driven by a wide variety of intrinsic shapes. Large velocity gradient radiative transfer modeling demonstrates the existence of a highly excited component that elevates the CO SLED of high-redshift main-sequence and starbursting galaxies above the typical values observed in the disk of the Milky Way. This excited component is dense and it encloses ~50% of the total molecular gas mass in main-sequence objects. We interpret the observed trends involving the CO excitation as to be mainly determined by a combination of large SFRs and compact sizes, as a large SigmaSFR is naturally connected with enhanced dense molecular gas fractions and higher dust and gas temperatures, due to increasing ultraviolet radiation fields, cosmic ray rates, as well as dust and gas coupling. We release the full data compilation and the ancillary information to the community.
656. 12CO/13CO ratio in 126 nearby galaxy centers
ID:
ivo://CDS.VizieR/J/A+A/635/A131
Title:
12CO/13CO ratio in 126 nearby galaxy centers
Short Name:
J/A+A/635/A131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ground-based measurements of 126 nearby galaxy centers in ^12^CO and 92 in ^13^CO in various low-J transitions. More than 60 galaxies were measured in at least four lines. The average relative intensities of the first four J ^12^CO transitions are 1.00:0.92:0.70:0.57. In the first three J transitions, the average ^12^CO-to-^13^CO intensity ratios are 13.0, 11.6, and 12.8, with individual values in any transition ranging from 5 to 25. The sizes of central CO concentrations are well defined in maps, but poorly determined by multi-aperture photometry. On average, the J=1-0 ^12^CO fluxes increase linearly with the size of the observing beam. CO emission covers only a quarter of the HI galaxy disks. Using radiative transfer models (RADEX), we derived model gas parameters. The assumed carbon elemental abundances and carbon gas depletion onto dust are the main causes of uncertainty. The new CO data and published [CI] and [CII] data imply that CO, C, and C^+^ each represent about one-third of the gas-phase carbon in the molecular interstellar medium. The mean beam-averaged molecular hydrogen column density is N(H_2_)=(1.5+/-0.2)10^21^cm^-2^. Galaxy center CO-to- H2 conversion factors are typically ten times lower than the 'standard' Milky Way X disk value, with a mean X(CO)=(1.9+/-0.2)10^19^cm^-2^/(K.km/s) and a dispersion 1.7. The corresponding [CI]-H_2_ factor is five times higher than X(CO), with X[CI]=(9+/-2)10^19^cm^-2^/(K.km/s). No unique conversion factor can be determined for [CII]. The low molecular gas content of galaxy centers relative to their CO intensities is explained in roughly equal parts by high central gas-phase carbon abundances, elevated gas temperatures, and large gas velocity dispersions relative to the corresponding values in galaxy disks.
657. CO datacube abd spectra of UGC 10214
ID:
ivo://CDS.VizieR/J/A+A/623/A154
Title:
CO datacube abd spectra of UGC 10214
Short Name:
J/A+A/623/A154
Date:
21 Oct 2021
Publisher:
CDS
Description:
Minor mergers play a crucial role in galaxy evolution. UGC 10214 (the Tadpole galaxy) is a prime example of this process in which a dwarf galaxy has interacted with a large spiral galaxy ~250 Myr ago and produced a perturbed disc and a giant tidal tail. We used a multi-wavelength dataset that partly consists of new observations (H{alpha}, HI, and CO) and partly of archival data to study the present and past star formation rate (SFR) and its relation to the gas and stellar mass at a spatial resolution down to 4 kpc. UGC 10214 is a high-mass (stellar mass M_*_=1.28x10^11^ M_{sun}_) galaxy with a low gas fraction (M_gas_/M_*_=0.24), a high molecular gas fraction (M_H2_/M_HI_=0.4), and a modest SFR (2-5 M_{sun}_/yr). The global SFR compared to its stellar mass places UGC 10214 on the galaxy main sequence (MS). The comparison of the molecular gas mass and current SFR gives a molecular gas depletion time of about ~2 Gyr (based on H{alpha}), comparable to those of normal spiral galaxies. Both from a comparison of the H{alpha} emission, tracing the current SFR, and far-ultraviolet (FUV) emission, tracing the recent SFR during the past tens of Myr, and also from spectral energy distribution fitting with CIGALE, we find that the SFR has increased by a factor of about 2-3 during the recent past. This increase is particularly noticeable in the centre of the galaxy where a pronounced peak of the H{alpha} emission is visible. A pixel-to-pixel comparison of the SFR, molecular gas mass, and stellar mass shows that the central region has had a depressed FUV-traced SFR compared to the molecular gas and the stellar mass, whereas the H{alpha}-traced SFR shows a normal level. The atomic and molecular gas distribution is asymmetric, but the position-velocity diagram along the major axis shows a pattern of regular rotation. We conclude that the minor merger has most likely caused variations in the SFR in the past that resulted in a moderate increase of the SFR, but it has not perturbed the gas significantly so that the molecular depletion time remains normal.
658. CO in group-dominant ellipticals
ID:
ivo://CDS.VizieR/J/A+A/618/A126
Title:
CO in group-dominant ellipticals
Short Name:
J/A+A/618/A126
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present IRAM 30m and APEX telescope observations of CO(1-0) and CO(2-1) lines in 36 group-dominant early-type galaxies, completing our molecular gas survey of dominant galaxies in the Complete Local-volume Groups Sample. We detect CO emission in 12 of the galaxies at >4{sigma} significance, with molecular gas masses in the range 0.01-6x10^8^M_{sun}_, as well as CO in absorption in the non-dominant group member galaxy NGC 5354. In total 21 of the 53 CLoGS dominant galaxies are detected in CO and we confirm our previous findings that they have low star formation rates (0.01-1M_{sun}_/yr) but short depletion times (<1Gyr) implying rapid replenishment of their gas reservoirs. Comparing molecular gas mass with radio luminosity, we find that a much higher fraction of our group-dominant galaxies (60+/-16%) are AGN-dominated than is the case for the general population of ellipticals, but that there is no clear connection between radio luminosity and the molecular gas mass. Using data from the literature, we find that at least 27 of the 53 CLoGS dominant galaxies contain HI, comparable to the fraction of nearby non-cluster early type galaxies detected in HI and significantly higher that the fraction in the Virgo cluster. We see no correlation between the presence of an X-ray detected intra-group medium and molecular gas in the dominant galaxy, but find that the HI-richest galaxies are located in X-ray faint groups. Morphological data from the literature suggests the cold gas component most commonly takes the form of a disk, but many systems show evidence of galaxy-galaxy interactions, indicating that they may have acquired their gas through stripping or mergers. We provide improved molecular gas mass estimates for two galaxies previously identified as being in the centres of cooling flows, NGC 4636 and NGC5846, and find that they are relatively molecular gas poor compared to our other detected systems.
659. CO in HCG galaxies with enhanced warm H_2_
ID:
ivo://CDS.VizieR/J/A+A/570/A24
Title:
CO in HCG galaxies with enhanced warm H_2_
Short Name:
J/A+A/570/A24
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galaxies in Hickson Compact Groups (HCGs) are believed to experience morphological transformations from blue, star-forming galaxies to red, early-type galaxies. Galaxies with a high ratio between the luminosities of the warm H_2_ to the 7.7micron PAH emission (so-called Molecular Hydrogen Emission Galaxies, MOHEGs) are predominantly in an intermediate phase, the green valley. Their enhanced H_2_ emission suggests that the molecular gas is affected in the transition. We study the properties of the molecular gas traced by CO in galaxies in HCGs with measured warm H_2_ emission in order to look for evidence of the perturbations affecting the warm H_2_ in the kinematics, morphology and mass of the molecular gas. We observed the CO(1-0) emission of 20 galaxies in HCGs and complemented our sample with 11 CO(1-0) spectra from the literature. Most of the galaxies have measured} warm H_2_ emission, and 14 of them are classified as MOHEGs. We mapped some of these galaxies in order to search for extra-galactic CO emission. We analyzed the molecular gas mass derived from CO(1-0), MH_2_, and its kinematics, and then compared it to the mass of the warm molecular gas, the stellar mass and star formation rate (SFR). Our results are the following. (i) The mass ratio between the CO-derived and the warm H_2_ molecular gas is in the same range as found for field galaxies. (ii) Some of the galaxies, mostly MOHEGs, have very broad CO linewidths of up to 1000km/s in the central pointing. The line shapes are irregular and show various components. (iii) In the mapped objects we found asymmetric distributions of the cold molecular gas. (iv) The star formation efficiency (=SFR/MH_2_) of galaxies in HCGs is very similar to isolated galaxies. No significant difference between MOHEGs and non-MOHEGs or between early-type and spiral galaxies has been found. In a few objects the SFE is significantly lower, indicating the presence of molecular gas that is not actively forming stars. (v) The molecular gas masses, MH_2_, and ratios MH_2_/Lk are lower in MOHEGs (predominantly early-types) than in non-MOHEGs (predominantly spirals). This trend remains when comparing MOHEGs and non-MOHEGs of the same morphological type. We found differences in the molecular gas properties of MOHEGs that support the view that they have suffered (or are presently suffering) perturbations of the molecular gas, as well as a decrease in the molecular gas content and associated SFR. Higher resolution observations of the molecular gas are needed to shed light on the nature of these perturbations and their cause.
660. COLA. III. AGN in compact IR galaxies
ID:
ivo://CDS.VizieR/J/ApJ/720/555
Title:
COLA. III. AGN in compact IR galaxies
Short Name:
J/ApJ/720/555
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from 4.8GHz Very Large Array (VLA) and global very long baseline interferometry (VLBI) observations of the northern half of the moderate FIR luminosity (median L_IR_=10^11.01^L_{sun}_) COLA (Compact Objects in Low-power AGNs) sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the galaxies observed. The radio luminosities of these cores (~10^21^W/Hz) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by active galactic nuclei (AGNs). These sub-parsec scale radio cores are preferentially detected toward galaxies whose VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star formation, we conclude that the AGN-powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central supermassive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity.