- ID:
- ivo://CDS.VizieR/J/A+A/654/A150
- Title:
- Gas and young stars in CMa OB1 assoc.
- Short Name:
- J/A+A/654/A150
- Date:
- 21 Mar 2022 09:18:01
- Publisher:
- CDS
- Description:
- The relationship between young stellar clusters and their respective parental molecular clouds remains an open issue. Recent inquiries consider the similarities between substructures of clouds and clusters and whether they are a coincidence or, rather, an indication of a physical relationship. To address these issues, we studied the CMa OB1/R1 region, which shows evidence of a complex star formation history. We obtained molecular cloud mapping with the IRAM-30 metre telescope to reveal the physical conditions of an unexplored side of the CMa region with the aim of comparing the morphology of the clouds to the distribution of young stellar objects (YSOs). We also studied the cloud kinematics in pursuit of gradients and jet signatures that could trace different star formation scenarios. The YSOs were selected on the basis of astrometric data from Gaia EDR3 that characterize the moving groups. The distance of 1099_-24_^+25^pc was obtained for the sample, based on the mean error-weighted parallax. Optical and near-infrared photometry was used to verify the evolutionary status and circumstellar characteristics of the YSOs. Among the selected candidates, we found 40 members associated with the cloud: 1 Class I, 11 Class II, and 28 Class III objects. Comparing the spatial distribution of the stellar population with the cores revealed by the ^13^CO map, we verified that peaks of emission coincide with the position of YSOs, confirming the association of these objects to their dense natal gas. Our observations support the large-scale scenario of the CMa shell-like structure formation as a relic of successive supernova events.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/422/941
- Title:
- Gas content in 1038 interacting galaxies
- Short Name:
- J/A+A/422/941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A study of the gas content in 1038 interacting galaxies, essentially selected from Arp (<VII/74>), Arp and Madore (<VII/170>), Vorontsov-Velyaminov (<VII/236>) catalogues and some of the published literature, is presented here. The data on the interstellar medium have been extracted from a number of sources in the literature and compared with a sample of 1916 normal galaxies. The mean values for each of the different ISM tracers (FIR, 21cm, CO lines, X-ray) have been estimated by means of survival analysis techniques, in order to take into account the presence of upper limits.
- ID:
- ivo://CDS.VizieR/J/ApJ/706/516
- Title:
- Gas content of star-forming galaxies
- Short Name:
- J/ApJ/706/516
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars do not form continuously distributed over star-forming galaxies. They form in star clusters of different masses. This nature of clustered star formation is taken into account in the theory of the integrated galactic stellar initial mass function (IGIMF) in which the galaxy-wide initial mass function (IMF) on galaxy-wide scales is calculated by adding all IMFs of young star clusters. For massive stars, the IGIMF is steeper than the universal IMF in star clusters and steepens with decreasing star formation rate (SFR) which is called the IGIMF effect. The current SFR and the total H{alpha} luminosity of galaxies therefore scale nonlinearly in the IGIMF theory compared to the classical case in which the galaxy-wide IMF is assumed to be constant and identical to the IMF in star clusters. Here we apply for the first time the revised SFR-L_H{alpha}_ relation on a sample of local volume star-forming galaxies with measured H{alpha} luminosities.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A135
- Title:
- Gas dynamics in Massive Dense Cores in Cygnus-X
- Short Name:
- J/A+A/527/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the kinematic properties of dense gas surrounding massive protostars in a sample of five Massive Dense Cores (MDCs) in Cygnus-X. The aim is to investigate whether turbulent support plays a major role in stabilizing the cores against a rapid fragmentation into Jeans-mass objects. Alternatively the observed kinematics could indicate a high level of dynamics suggesting that the cores are actually not in equilibrium and dynamical processes could be the main driver to build up the final stellar masses.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A113
- Title:
- Gas dynamics in tidal dwarf galaxies
- Short Name:
- J/A+A/584/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tidal dwarf galaxies (TDGs) are recycled objects that form within the collisional debris of interacting and merging galaxies. They are expected to be devoid of non-baryonic dark matter, since they can only form from dissipative material ejected from the discs of the progenitor galaxies. We investigate the gas dynamics in a sample of six bona fide TDGs around three interacting and post-interacting systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace"). For NGC 4694 and NGC 5291, we analyse existing HI data from the Very Large Array (VLA), while for NGC 7252 we present new HI observations from the Jansky VLA, together with long-slit and integral-field optical spectroscopy. For all six TDGs, the HI emission can be described by rotating disc models. These HI discs, however, have undergone less than a full rotation since the time of the interaction/merger event, raising the question of whether they are in dynamical equilibrium. Assuming that these discs are in equilibrium, the inferred dynamical masses are consistent with the observed baryonic masses, implying that TDGs are devoid of dark matter. This puts constraints on putative "dark discs" (either baryonic or non-baryonic) in the progenitor galaxies. Moreover, TDGs seem to systematically deviate from the baryonic Tully-Fisher relation. These results provide a challenging test for alternative theories like MOND.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2888
- Title:
- Gas exchanges between galaxies and IGM
- Short Name:
- J/MNRAS/421/2888
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a representative sample of 65 intermediate-mass galaxies at z~0.6, we have investigated the interplay between the main ingredients of chemical evolution: metal abundance, gas mass, stellar mass and star formation rate (SFR). All quantities have been estimated using deep spectroscopy and photometry from ultraviolet to infrared and assuming an inversion of the Kennicutt-Schmitt law for the gas fraction. Six billion years ago, galaxies had a mean gas fraction of 32+/-3 per cent, i.e. twice that of their local counterparts. Using higher redshift samples from the literature, we explore the gas phases and estimate the evolution of the mean gas fraction of distant galaxies over the last 11Gyr.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A59
- Title:
- Gas kinematics in CALIFA survey
- Short Name:
- J/A+A/573/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [OII] {lambda}{lambda}3726,3729, [OIII] {lambda}{lambda}4959,5007, H{alpha}+[NII] {lambda}{lambda}6548,6584, and [SII]{lambda}{lambda}6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [OIII] {lambda}{lambda}4959,5007 emission line profiles.
- ID:
- ivo://CDS.VizieR/J/A+A/520/A109
- Title:
- Gas kinematics of spiral galaxies
- Short Name:
- J/A+A/520/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We trace the interaction processes of galaxies at intermediate redshift by measuring the irregularity of their ionized gas kinematics, and investigate these irregularities as a function of the environment (cluster versus field) and of morphological type (spiral versus irregular). We obtain the gas velocity fields by placing three parallel and adjacent VLT/FORS2 slits on each galaxy. To quantify irregularities in the gas kinematics, we use three indicators: the standard deviation of the kinematic position angle ({sigma}_PA_), the mean deviation of the line of sight velocity profile from the cosine form which is measured using high order Fourier terms (k_3,5_/k_1_) and the average misalignment between the kinematical and photometric major axes ({Delta}{phi}). These indicators are then examined together with some photometric and structural parameters (measured from HST and FORS2 images in the optical) such as the disk scale length, rest-frame colors, asymmetry, concentration, Gini coefficient and M20 . Our sample consists of 92 distant galaxies. 16 cluster (z~0.3 and z~0.5) and 29 field galaxies (0.10<=z<=0.91, mean z=0.44) of these have velocity fields with sufficient signal to be analyzed. To compare our sample with the local universe, we also analyze a sample from the SINGS survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/1299
- Title:
- Gas-phase element depletions in the ISM
- Short Name:
- J/ApJ/700/1299
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A study of gas-phase element abundances reported in the literature for 17 different elements sampled over 243 sight lines in the local part of our Galaxy reveals that the depletions into solid form (dust grains) are extremely well characterized by trends that employ only three kinds of parameters. One is an index that describes the overall level of depletion applicable to the gas in any particular sight line, and the other two represent linear coefficients that describe how to derive each element's depletion from this sight-line parameter. The information from this study reveals the relative proportions of different elements that are incorporated into dust at different stages of grain growth.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/80
- Title:
- Gas phase oxygen abundances for HII regions
- Short Name:
- J/ApJ/887/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of metals within a galaxy traces the baryon cycle and the buildup of galactic disks, but the detailed gas phase metallicity distribution remains poorly sampled. We have determined the gas phase oxygen abundances for 7138 HII regions across the disks of eight nearby galaxies using Very Large Telescope/Multi Unit Spectroscopic Explorer (MUSE) optical integral field spectroscopy as part of the PHANGS-MUSE survey. After removing the first-order radial gradients present in each galaxy, we look at the statistics of the metallicity offset ({Delta}O/H) and explore azimuthal variations. Across each galaxy, we find low ({sigma}=0.03-0.05dex) scatter at any given radius, indicative of efficient mixing. We compare physical parameters for those HII regions that are 1{sigma} outliers toward both enhanced and reduced abundances. Regions with enhanced abundances have high ionization parameter, higher H{alpha} luminosity, lower H{alpha} velocity dispersion, younger star clusters, and associated molecular gas clouds showing higher molecular gas densities. This indicates recent star formation has locally enriched the material. Regions with reduced abundances show increased H{alpha} velocity dispersions, suggestive of mixing introducing more pristine material. We observe subtle azimuthal variations in half of the sample, but cannot always cleanly associate this with the spiral pattern. Regions with enhanced and reduced abundances are found distributed throughout the disk, and in half of our galaxies we can identify subsections of spiral arms with clearly associated metallicity gradients. This suggests spiral arms play a role in organizing and mixing the interstellar medium.