- ID:
- ivo://CDS.VizieR/J/ApJ/857/19
- Title:
- ALMA view of GMCs in NGC 300
- Short Name:
- J/ApJ/857/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a ^12^CO(2-1) survey of several molecular gas complexes in the vicinity of HII regions within the spiral galaxy NGC300 using the Atacama Large Millimeter Array (ALMA). Our observations attain a resolution of 10pc and 1km/s, sufficient to fully resolve giant molecular clouds (GMCs) and the highest obtained to date beyond the Local Group. We use the CPROPS algorithm to identify and characterize 250 GMCs across the observed regions. GMCs in NGC300 appear qualitatively and quantitatively similar to those in the Milky Way disk: they show an identical scaling relationship between size R and linewidth {Delta}V ({Delta}V{propto}R^0.48+/-0.05^), appear to be mostly in virial equilibrium, and are consistent with having a constant surface density of about 60M_{sun}_/pc^2^. The GMC mass spectrum is similar to those in the inner disks of spiral galaxies (including the Milky Way). Our results suggest that global galactic properties such as total stellar mass, morphology, and average metallicity may not play a major role in setting GMC properties, at least within the disks of galaxies on the star-forming main sequence. Instead, GMC properties may be more strongly influenced by local environmental factors such as the midplane disk pressure. In particular, in the inner disk of NGC 300, we find this pressure to be similar to that in the local Milky Way but markedly lower than that in the disk of M51, where GMCs are characterized by systematically higher surface densities and a higher coefficient for the size-linewidth relation.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/869
- Title:
- A mapping survey of massive CO cores
- Short Name:
- J/MNRAS/391/869
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We mapped 21 star-forming regions with the ^12^CO, ^13^CO and C^18^O (1-0) lines using the 13.7-m telescope of Purple Mount Observatory. This mapping survey resolved 53 ^13^CO cores, of which 22 are sourceless. We obtained the physical parameters of these cores. The relation between ^13^CO linewidth and core size and that between column density and core size were analysed. The cores 00211+6549-1 and 22566+5830 were found to have outflows. Systematic VLSR shifts were detected in nine regions: 00211+6549, 00232+6437, 05168+3634, 19199+1358, 20160+3911, 22566+5830, 23042+6000, S146 and S270. Signatures of infall and cloud collision were found in regions 18507+0121 and 19199+1358, respectively. We studied the mass function of these ^13^CO cores. The core masses range from 3.40 to 4.64x10^4^M_{sun}_, and the core mass function is a power-law distribution of index -0.82+/-0.04.
- ID:
- ivo://CDS.VizieR/J/A+A/534/A102
- Title:
- AMIGA IX. Molecular gas properties
- Short Name:
- J/A+A/534/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterize the molecular gas content (ISM cold phase) using CO emission of a redshift-limited subsample of isolated galaxies from the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) project in order to provide a comparison sample for studies of galaxies in different environments. We present the ^12^CO(1-0) data for 273 AMIGA galaxies, most of them (n=186) from our own observations with the IRAM 30m and the FCRAO 14m telescopes and the rest from the literature. We constructed a redshift-limited sample containing galaxies with 1500km/s<v<5000km/s and excluded objects with morphological evidence of possible interaction. This sample (n=173) is the basis for our statistical analysis. It contains galaxies with molecular gas masses, MH2, in the range of ~10^8^-10^10^M_{sun}_. It is dominated, both in absolute number and in detection rate, by spiral galaxies of type T=3-5 (Sb-Sc). Most galaxies were observed with a single pointing towards their centers. Therefore, we performed an extrapolation to the total molecular gas mass expected in the entire disk based on the assumption of an exponential distribution. We then studied the relationships between MH2 and other galactic properties.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A102
- Title:
- APEX CO and HI observations of Lupus I
- Short Name:
- J/A+A/608/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lupus I cloud is found between the Upper Scorpius (USco) and Upper Centaurus-Lupus (UCL) subgroups of the Scorpius-Centaurus OB association, where the expanding USco HI shell appears to interact with a bubble currently driven by the winds of the remaining B stars of UCL. Aims. We investigate whether the Lupus I molecular could have formed in a colliding flow, and in particular, how the kinematics of the cloud might have been influenced by the larger scale gas dynamics. We performed APEX ^13^CO(2-1)and C^18^O(2-1) line observations of three distinct parts of Lupus I that provide kinematic information on the cloud at high angular and spectral resolution. We compare those results to the atomic hydrogen data from the GASS HI survey and our dust emission results presented in the previous paper. Based on the velocity information, we present a geometric model for the interaction zone between the USco shell and the UCL wind bubble. We present evidence that the molecular gas of Lupus Iis tightly linked to the atomic material of the USco shell. The CO emission in Lupus Iis found mainly at velocities between v_LSR_=3-6km/s, which is in the same range as the HI velocities. Thus, the molecular cloud is co-moving with the expanding USco atomic HI shell. The gas in the cloud shows a complex kinematic structure with several line-of-sight components that overlay each other. The nonthermal velocity dispersion is in the transonic regime in all parts of the cloud and could be injected by external compression. Our observations and the derived geometric model agree with a scenario in which Lupus Iis located in the interaction zone between the USco shell and the UCL wind bubble. The kinematics observations are consistent with a scenario in which the Lupus Icloud formed via shell instabilities. The particular location of Lupus I between USco and UCL suggests that counterpressure from the UCL wind bubble and pre-existing density enhancements, perhaps left over from the gas stream that formed the stellar subgroups, may have played a role in its formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/940
- Title:
- ATLAS3D project. IV.
- Short Name:
- J/MNRAS/414/940
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a survey for CO J=1-0 and J=2-1 emission in the 260 early-type galaxies of the volume-limited ATLAS3D sample, with the goal of connecting their star formation and assembly histories to their cold gas content. This is the largest volume-limited CO survey of its kind and is the first to include many Virgo cluster members. Sample members are dynamically hot galaxies with a median stellar mass ~3x10^10^M_{sun}_; they are selected by their morphology rather than colour, and the bulk of them lie on the red sequence. The overall CO detection rate is 56/259=0.22+/-0.03, with no dependence on the K luminosity and only a modest dependence on the dynamical mass. There are a dozen CO detections among the Virgo cluster members; statistical analysis of their H_2_ mass distributions and their dynamical status within the cluster shows that the cluster's influence on their molecular masses is subtle at best, even though (unlike spirals) they seem to be virialized within the cluster. We suggest that the cluster members have retained their molecular gas through several Gyr residences in the cluster.
- ID:
- ivo://CDS.VizieR/J/ApJS/252/29
- Title:
- BAT AGN Spectroscopic Survey. XX. Molecular gas
- Short Name:
- J/ApJS/252/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01<z<0.05) hard-X-ray-selected active galactic nucleus (AGN) galaxies, drawn from the 70-month catalog of Swift's Burst Alert Telescope (BAT), with 200 new CO(2-1) line measurements obtained with the James Clerk Maxwell Telescope and the Atacama Pathfinder Experiment telescope. We find that AGN in massive galaxies (log(M_*_/M_{sun}_)>10.5) tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies, with no evidence that AGN feedback affects the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (~5% versus 49%) compared to inactive galaxies. The likelihood of a given galaxy hosting an AGN (L_bol_>10^44^erg/s) increases by ~10-100 between a molecular gas mass of 10^8.7^M_{sun}_ and 10^10.2^M_{sun}_. AGN galaxies with a higher Eddington ratio (log(L/L_Edd_)>-1.3) tend to have higher molecular gas masses and gas fractions. The log(NH/cm^-2^)>23.4) of AGN galaxies with higher column densities are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy-wide molecular gas. The significant average link of host-galaxy molecular gas supply to supermassive black hole (SMBH) growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties, and the redshift evolution of star formation and SMBH growth.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A76
- Title:
- California molecular cloud CO datacubes
- Short Name:
- J/A+A/642/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dense molecular filaments are central to the star formation process, but the detailed manner in which they fragment into prestellar cores is not well understood yet. Here, we investigate the fragmentation properties and dynamical state of several star-forming filaments in the X-shaped nebula region of the California molecular cloud in an effort to shed some light on this issue. We used multiwavelength far-infrared images from Herschel as well as the getsources and getfilaments extraction methods to identify dense cores and filaments in the region and derive their basic properties. We also used a map of ^13^CO(2-1) emission from the Arizona 10m Submillimeter Telescope (SMT) to constrain the dynamical state of the filaments. We identified ten filaments with aspect ratios of AR>4 and column density contrasts of C>0.5, as well as 57 dense cores, including two protostellar cores, 20 robust prestellar cores, 11 candidate prestellar cores, and 24 unbound starless cores. All ten filaments have roughly the same deconvolved full width at half maximum (FWHM), with a median value of 0.12+/-0.03pc, which is independent of their column densities ranging from <10^21^cm^-2^ to >10^22^cm^-2^. Two star-forming filaments (# 8 and # 10) stand out since they harbor quasi-periodic chains of dense cores with a typical projected core spacing of ~0.15pc. These two filaments have thermally supercritical line masses and are not static. Filament 8 exhibits a prominent transverse velocity gradient, suggesting that it is accreting gas from the parent cloud gas reservoir at an estimated rate of ~40+/-10M_{sun}_/Myr/pc. Filament 10 includes two embedded protostars with outflows and it is likely at a somewhat later evolutionary stage than filament 8. In both cases, the observed (projected) core spacing is similar to the filament width and significantly shorter than the canonical separation of ~4 times the filament width predicted by classical cylinder fragmentation theory. It is unlikely that projection effects can explain this discrepancy. We suggest that the continuous accretion of gas onto the two star-forming filaments, as well as the geometrical bending of the filaments, may account for the observed core spacing. Our findings suggest that the characteristic fragmentation lengthscale of molecular filaments is quite sensitive to external perturbations from the parent cloud, such as the gravitational accretion of ambient material.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A22
- Title:
- CARLA J1103+3449 cluster datacube
- Short Name:
- J/A+A/641/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Passive early-type galaxies dominate cluster cores at z<~1.5. At higher redshift, cluster core galaxies are observed to have on-going star-formation, which is fuelled by cold molecular gas.We measured the molecular gas reservoir of the central region around the radioloud active galactic nucleus (AGN) in the cluster CARLA J1103+3449 at z=1.44 using NOEMA. The AGN synchrotron emission dominates the continuum emission at 94.48GHz, and we measured its flux at the AGN position and at the position of two radio jets. Combining our measurements with published results over the range 4.71GHz-94.5GHz, and assuming S_synch_{prop.to}{nu}^-{alpha}^, we obtain a flat spectral index of = 0:14 0:03 for the AGN core emission, and a steeper index of {alpha}=1.43+/-0.04 and {alpha}=1.15+/-0.04 at positions close to the western and eastern lobes, respectively. The total spectral index is {alpha}=0.92+/-0.02 over the range 73.8MHz-94.5GHz.We detect two CO(2-1) emission lines, both blueshifted with respect to the AGN. Their emission corresponds to two regions, 17kpc southeast and 14kpc southwest of the AGN, not associated with galaxies. In these two regions, we find a total massive molecular gas reservoir of M^tot^_gas_=3.9+/-0.4x10^10^M_{sun}_, which dominates (>~60%) the central total molecular gas reservoir. These results can be explained by massive cool gas flows in the center of the cluster. The AGN early-type host is not yet quenched; its star formation rate is consistent with being on the main sequence of star-forming galaxies in the field (star formation rate ~30-140M_[sun}_/yr), and the cluster core molecular gas reservoir is expected to feed the AGN and the host star formation before quiescence. The other confirmed cluster members show star formation rates at 2 below the field main sequence at similar redshifts and do not have molecular gas masses larger than galaxies of similar stellar mass in the field.
19. 3C 236 CO maps
- ID:
- ivo://CDS.VizieR/J/A+A/549/A58
- Title:
- 3C 236 CO maps
- Short Name:
- J/A+A/549/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is growing observational evidence of active galactic nuclei (AGN) feedback on the ISM of radio-quiet and radio-loud galaxies. While AGN feedback is expected to be more common at high redshift objects, the study of local universe galaxies help to better characterize the different manifestations of AGN feedback.AIMS. Molecular line observations can be used to quantify the mass and energy budget of the gas affected by AGN feedback. We study the emission of molecular gas in 3C 236, a Faranoff-Riley type 2 (FR II) radio source at z~0.1, and search for the footprints of AGN feedback. 3C 236 shows signs of a reactivation of its AGN triggered by a recent minor merger episode. Observations have also previously identified an extreme HI outflow in this source. The IRAM Plateau de Bure interferometer (PdBI) has been used to study the distribution and kinematics of molecular gas in 3C 236 by imaging with high spatial resolution (0.6") the emission of the 2-1 line of ^12^CO in the nucleus of the galaxy. We have searched for outflow signatures in the CO map. We have also derived the star-formation rate (SFR) in 3C 236 using data available from the literature at UV, optical and IR wavelengths, to determine the star-formation efficiency of molecular gas. The CO emission in 3C 236 comes from a spatially resolved ~1.4" (2.6kpc)-diameter disk characterized by a regular rotating pattern. Within the limits imposed by the sensitivity and velocity coverage of the CO data, we do not detect any outflow signatures in the cold molecular gas. The disk has a cold gas mass M(H_2_)~2.1x10^9^M_{sun}_. Based on CO we determine a new value for the redshift of the source z_CO_=0.09927+/-0.0002. The similarity between the CO and HI profiles indicates that the deep HI absorption in 3C 236 can be accounted for by a rotating HI structure. This restricts the evidence of HI outflow only to the most extreme velocities. In the light of the new redshift value, the analysis of the ionized gas kinematics reveals a fast (~1000km/s) outflow. As for the CO emitting gas, outflow signatures are nevertheless absent in the warm molecular gas emission traced by infrared H_2_ lines. The star-formation efficiency in 3C 236 is consistent with the value measured in normal galaxies, which follow the canonical Kennicutt-Schmidt (KS) relation. This result, confirmed to hold in other young radio sources examined in this work, is in stark contrast with the factor of 10-50 lower SFE that has been claimed to characterize evolved powerful radio galaxies. There are no signs of ongoing AGN feedback on the molecular ISM of 3C 236. The recent reactivation of the AGN in 3C 236 (about ~10^5^yr ago) is a likely explanation for the early evolutionary status of its molecular disk.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A8
- Title:
- Cepheus E CO, OH and OI spectra
- Short Name:
- J/A+A/602/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Protostellar jets and outflows are key features of the star-formation process, and primary processes of the feedback of young stars on the interstellar medium. Understanding the underlying shocks is necessary to explain how jet and outflow systems are launched, and to quantify their chemical and energetic impacts on the surrounding medium. We performed a high-spectral resolution study of the [OI]63um emission in the outflow of the intermediate-mass Class 0 protostar Cep E-mm. The goal is to determine the structure of the outflow, to constrain the chemical conditions in the various components, and to understand the nature of the underlying shocks, thus probing the origin of the mass-loss phenomenon. We present observations of the OI ^3^P_1_ -> ^3^P_2_, OH between ^2^{Pi}_1/2_ J=3/2 and J=1/2 at 1837.8GHz, and CO (16-15) lines with the GREAT receiver onboard SOFIA towards three positions in the Cep E protostellar outflow: Cep E-mm (the driving protostar), Cep E-BI (in the southern lobe), and Cep E-BII (the terminal position in the southern lobe).
