- ID:
- ivo://CDS.VizieR/J/ApJ/867/165
- Title:
- CO molecular clumps in Henize 2-10 dwarf galaxy
- Short Name:
- J/ApJ/867/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Atacama Large Millimeter/Submillimeter Array CO(3-2) observations at 0.3" resolution of He 2-10, a starburst dwarf galaxy and possible high-z galaxy analog. The warm dense gas traced by CO(3-2) is found in clumpy filaments that are kinematically and spatially distinct. The filaments have no preferred orientation or direction; this may indicate that the galaxy is not evolving into a disk galaxy. Filaments appear to be feeding the active starburst; the velocity field in one filament suggests acceleration onto an embedded star cluster. The relative strengths of CO(3-2) and radio continuum vary strongly on decaparsec scales in the starburst. There is no CO(3-2) clump coincident with the nonthermal radio source that has been suggested to be an AGN, nor unusual kinematics. The kinematics of the molecular gas show significant activity that is apparently unrelated to the current starburst. The longest filament, east of the starburst, has a pronounced shear of FWHM ~40km/s across its ~50pc width over its entire ~0.5kpc length. The cause of the shear is not clear. This filament is close in projection to a "dynamically distinct" CO feature previously seen in CO(1-0). The most complex region and the most highly disturbed gas velocities are in a region 200pc south of the starburst. The CO(3-2) emission there reveals a molecular outflow, of line width FWZI~120-140km/s, requiring an energy >~10^53^erg/s. There is at present no candidate for the driving source of this outflow.
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- ID:
- ivo://CDS.VizieR/J/A+A/564/A128
- Title:
- Continuum and CO maps of 3C 293
- Short Name:
- J/A+A/564/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Powerful radio galaxies show evidence of ongoing active galactic nuclei (AGN) feedback, mainly in the form of fast, massive outflows. But it is not clear how these outflows affect the star formation of their hosts. We investigate the different manifestations of AGN feedback in the evolved, powerful radio source 3C 293 and their impact on the molecular gas of its host galaxy, which harbors young star-forming regions and fast outflows of H i and ionized gas. We study the distribution and kinematics of the molecular gas of 3C 293 using high spatial resolution observations of the ^12^CO(1-0) and ^12^CO(2-1) lines, and the 3mm and 1 continuum taken with the IRAM Plateau de Bure interferometer. We mapped the molecular gas of 3C 293 and compared it with the dust and star-formation images of the host. We searched for signatures of outflow motions in the CO kinematics, and re-examined the evidence of outflowing gas in the HI spectra. We also derived the star formation rate (SFR) and star formation efficiency (SFE) of the host with all available SFR tracers from the literature, and compared them with the SFE of young and evolved radio galaxies and normal star-forming galaxies. The ^12^CO(1-0) emission line shows that the molecular gas in 3C 293 is distributed along a massive (M(H_2_)~2.2x10^10^M_{sun}_) ~24" (21kpc) diameter warped disk, that rotates around the AGN. Our data show that the dust and the star formation are clearly associated with the CO disk. The ^12^CO(2-1) emission is located in the inner 7kpc (diameter) region around the AGN, coincident with the inner part of the ^12^CO(1-0) disk. Both the ^12^CO(1-0) and ^12^CO(2-1) spectra reveal the presence of an absorber against the central regions of 3C 293 that is associated with the disk. We do not detect any fast (500km/s) outflow motions in the cold molecular gas. The host of 3C 293 shows an SFE consistent with the Kennicutt-Schmidt law of normal galaxies and young radio galaxies, and it is 10-50 times higher than the SFE estimated with the 7.7um PAH emission of evolved radio galaxies. Our results suggest that the apparently low SFE of evolved radio galaxies may be caused by an underestimation of the SFR and/or an overestimation of the molecular gas densities in these sources. The molecular gas of 3C 293, while not incompatible with a mild AGN-triggered flow, does not reach the high velocities (500km/s) observed in the HI spectrum. We find no signatures of AGN feedback in the molecular gas of 3C 293.
- ID:
- ivo://CDS.VizieR/J/A+A/309/581
- Title:
- CO observations of clouds in IC 1396 region
- Short Name:
- J/A+A/309/581
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- ^12^CO and ^13^CO (1-0) parameters are observed for selected clouds and cloud cores (or part of clouds) in the region of IC 1396
- ID:
- ivo://CDS.VizieR/VII/64
- Title:
- CO Observations of Galaxies
- Short Name:
- VII/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a complete summary of all observations of CO isotopes in galaxies up to spring 1984. It consists of seven tables. Refs.dat describes the reference for CO observations of galaxies. Telescop.dat describes the properties of the telescopes used for observations. Detect.dat and uprlmits.dat contain a compilation of data on galaxies that have been observed in CO. Most of the characteristics listed here are observed properties. The detected galaxies are listed first, followed by galaxies with upper limits. Upper limits are given for detected galaxies if the detection is disputed or if the limits refer to transitions or regions that have not yet been detected. Temp.dat is a comparison of the antenna temperature scales used in the references in this catalog. Maps.dat lists the coverage, resolution, observed structure of CO maps of galaxies, and notes.dat contains notes to tables.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A107
- Title:
- CO observations of major merger pairs at z=0
- Short Name:
- J/A+A/627/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CO observations of 78 spiral galaxies in local merger pairs. These galaxies represent a subsample of a Ks-band-selected sample consisting of 88 close major-merger pairs (HKPAIRs), 44 spiral-spiral (S+S) pairs, and 44 spiral-elliptical (S+E) pairs, with separation <20h^-1^kpc and mass ratio <2.5. For all objects, the star formation rate (SFR) and dust mass were derived from Herschel PACS and SPIRE data, and the atomic gas mass, MHI, from the Green Bank Telescope HI observations. The complete data set allows us to study the relation between gas (atomic and molecular) mass, dust mass, and SFR in merger galaxies. We derive the molecular gas fraction (M_H2_/M*), molecular-to-atomic gas mass ratio (M_H2_/M_HI_), gas-to-dust mass ratio and SFE (=SFR/M_H2_) and study their dependences on pair type (S+S compared to S+E), stellar mass, and the presence of morphological interaction signs. We find an overall moderate enhancement (~2x) in both molecular gas fraction (M_H2_/M*) and molecular-to-atomic gas ratio (M_H2_/M_HI_) for star-forming galaxies in major-merger pairs compared to non-interacting comparison samples, whereas no enhancement was found for the SFE nor for the total gas mass fraction ((MHI+MH2)/M^Cstar). When divided into S+S and S+E, low mass and high mass, and with and without interaction signs, there is a small difference in SFE, a moderate difference in M_H2_/M*, and a strong difference in M_H2_/M_HI_ between subsamples. For the molecular-to-atomic gas ratio M_H2_/M_HI_, the difference between S+S and S+E subsamples is 0.55+/-0.18dex and between pairs with and without interaction signs is 0.65+/-0.16dex. Together, our results suggest that (1) star formation enhancement in close major-merger pairs occurs mainly in S+S pairs after the first close encounter (indicated by interaction signs)^Mbecause the HI gas is compressed into star-forming molecular gas by the tidal torque; and (2) this effect is much weakened in the S+E pairs.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A104
- Title:
- CO observations of post-AGB stars
- Short Name:
- J/A+A/557/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is a group of binary post-AGB stars that show conspicuous near infrared (NIR) excess, which is usually assumed to arise from hot dust in very compact possibly rotating disks. These stars are surrounded by significantly fainter nebulae than the standard, well studied protoplanetary and planetary nebulae (PPNe, PNe). We aim to identify and study extended rotating disks around these stars and shed light on the role of disks in the formation and shaping of planetary nebulae. We present high-sensitivity mm-wave observations of CO lines in 24 objects of this type. The resulting CO lines are compared with profiles expected to arise from rotating disks, from both theoretical and observational grounds. We derive simple formulae that allow us to determine the mass of the CO-emitting gas and estimate its extent. The reliability and uncertainty of the methods are also widely discussed. CO emission is detected in most observed sources, and the line profiles show that the emissions very probably come from disks in rotation. We derive typical values of the disk mass between 10^-3^ and 10^-2^M_{sun}_, about two orders of magnitude lower than the (total) masses of standard PPNe. The high-detection rate (upper limits being not very significant) clearly confirm that the NIR excess of these stars arises from compact disks in rotation, which are likely the inner parts of those found here. Low-velocity outflows are also found in about eight objects with moderate expansion velocities of ~10km/s, to be compared with the velocities of about 100km/s often found in standard PPNe. Except for two sources with complex profiles, the outflowing gas in our objects represents a minor nebular component. Our simple estimates of the typical disk sizes yields values ~0.5-1arcsec, which is between 5x10^15^ and 3x10^16^cm. Estimates of the linear momenta carried by the outflows, which can only be performed in a few well studied objects, also yield moderate values when compared to the linear momenta that can be released by the stellar radiation pressure (contrary, again, to the case of the very massive and fast bipolar outflows in $standard$ PPNe that are strongly overluminous). The mass and dynamics of nebulae around various classes of post-AGB stars differ very significantly, and we can expect the formation of PNe with very different properties.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A64
- Title:
- CO observations of the IC443 SNR
- Short Name:
- J/A+A/644/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova remnants (SNRs) represent a major feedback source from stars in the interstellar medium of galaxies. During the latest stage of supernova explosions, shock waves produced by the initial blast modify the chemistry of gas and dust, inject kinetic energy into the surroundings, and may alter star formation characteristics. Simultaneously, gamma-ray emission is generated by the interaction between the ambient medium and cosmic rays (CRs), including those accelerated in the early stages of the explosion. We study the stellar and interstellar contents of IC443, an evolved shell-type SNR at a distance of 1.9kpc with an estimated age of 30kyr. We aim to measure the mass of the gas and characterize the nature of infrared point sources within the extended G region, which corresponds to the peak of gamma-ray emission detected by VERITAS and Fermi. We performed 10'x10' mapped observations of ^12^CO, ^13^CO J=1-0, J=2-1, and J=3-2 pure rotational lines, as well as C^18^O J=1-0 and J=2-1 obtained with the IRAM 30m and APEX telescopes over the extent of the gamma-ray peak to reveal the molecular structure of the region. We first compared our data with local thermodynamic equilibrium models. We estimated the optical depth of each line from the emission of the isotopologs ^13^CO and C^18^O. We used the population diagram and large velocity gradient assumption to measure the column density, mass, and kinetic temperature of the gas using ^12^CO and ^13^CO lines. We used complementary data (stars, gas, and dust at multiple wavelengths) and infrared point source catalogs to search for protostar candidates. Our observations reveal four molecular structures: a shocked molecular clump associated with emission lines extending between -31 and 16km/s, a quiescent, dark cloudlet associated with a line width of ~2km/s, a narrow ring-like structure associated with a line width of ~1.5km/s, and a shocked knot. We measured a total mass of ~230, ~90, ~210, and ~4M_{sun}_, respectively, for the cloudlet, ring-like structure, shocked clump, and shocked knot. We measured a mass of ~1100M_{sun}_ throughout the rest of the field of observations where an ambient cloud is detected. We found 144 protostar candidates in the region. Our results emphasize how the mass associated with the ring-like structure and the cloudlet cannot be overlooked when quantifying the interaction of CRs with the dense local medium. Additionally, the presence of numerous possible protostars in the region might represent a fresh source of CRs, which must also be taken into account in the interpretation of gamma-ray observations in this region.
- ID:
- ivo://CDS.VizieR/J/A+A/569/A81
- Title:
- CO observations towards W44E and W44F with APEX
- Short Name:
- J/A+A/569/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- When supernova blast waves interact with nearby molecular clouds, they send slower shocks into these clouds. The resulting interaction regions provide excellent environments for the use of MHD shock models to constrain the physical and chemical conditions in these regions. The interaction of supernova remnants (SNRs) with molecular clouds gives rise to strong molecular emission in the far-IR and sub-mm wavelength regimes. The application of MHD shock models in the interpretation of this line emission can yield valuable information on the energetic and chemical impact of supernova remnants. New mapping observations with the APEX telescope in ^12^CO (3-2), (4-3), (6-5), (7-6) and ^13^CO (3-2) towards two regions in the supernova remnant W44 are presented. Integrated intensities are extracted on five different positions, corresponding to local maxima of CO emission. The integrated intensities are compared to the outputs of a grid of models, which combine an MHD shock code with a radiative transfer module based on the 'large velocity gradient' approximation. Results: All extracted spectra show ambient and line-of-sight components as well as blue- and red-shifted wings indicating the presence of shocked gas. Basing the shock model fits only on the highest-lying transitions that unambiguously trace the shock-heated gas, we find that the observed CO line emission is compatible with non-stationary shocks and a pre-shock density of 10^4^cm^-3^. The ages of the modelled shocks scatter between values of ~1000 and ~3000 years. The shock velocities in W44F are found to lie between 20 and 25km/s, while in W44E fast shocks (30-35km/s) as well as slower shocks (~20km/s) are compatible with the observed spectral line energy diagrams. The pre-shock magnetic field strength components perpendicular to the line-of-sight in both regions have values between 100 and 200uG. Our best-fitting models allow us to predict the full ladder of CO transitions, the shocked gas mass in one beam as well as the momentum- and energy injection.
- ID:
- ivo://CDS.VizieR/J/ApJS/230/17
- Title:
- CO obs. of MCs in the Extreme Outer Galaxy region
- Short Name:
- J/ApJS/230/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an unbiased CO survey in the Galactic range of 34.75{deg}<=l<=45.25{deg} and -5.25{deg}<=b<=5.25{deg}, and the velocity range beyond the Outer arm. A total of 168 molecular clouds (MCs) are identified within the Extreme Outer Galaxy (EOG) region, and 31 of these MCs are associated with ^13^CO emission. However, none of them show significant C^18^O emission under the current detection limit. The typical size and mass of these MCs are 5pc and 3x10^3^M_{sun}_, implying a lack of large and massive MCs in the EOG region. Similar to MCs in the outer Galaxy, the velocity dispersions of EOG clouds are also correlated with their sizes; however, they are well displaced below the scaling relationship defined by the inner Galaxy MCs. These MCs with a median Galactocentric radius of 12.6kpc show very different distributions from those of the MCs in the Outer arm published in our previous paper, while roughly following the Outer Scutum-Centaurus arm defined by Dame & Thaddeus (2011ApJ...734L..24D). This result may provide robust evidence for the existence of the Outer Scutum-Centaurus arm. The lower limit of the total mass of this segment is about 2.7x10^5^M_{sun}_, which is about one magnitude lower than that of the Outer arm. The mean thickness of the gaseous disk is about 1.45{deg} or 450pc, and the scale height is about 1.27{deg}, or 400pc above the b=0{deg} plane. The warp traced by CO emission is very obvious in the EOG region and its amplitude is consistent with the predictions by other warp models using different tracers, such as dust, HI, and stellar components of our Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJS/254/3
- Title:
- CO obs. of molecular clouds in the MW midplane
- Short Name:
- J/ApJS/254/3
- Date:
- 17 Jan 2022 11:34:49
- Publisher:
- CDS
- Description:
- In this work, we study the properties of molecular clouds in the second quadrant of the Milky Way Midplane, from l=104.75{deg} to l=119.75{deg}, and b=-5.25{deg} to b=5.25{deg}, using the ^12^CO, ^13^CO, and C^18^O J=1-0 emission line data from the Milky Way Imaging Scroll Painting project. We identify 857 and 300 clouds in the ^12^CO and ^13^CO spectral cubes, respectively, using the DENDROGRAM + SCIMES algorithms. The distances of the molecular clouds are estimated, and physical properties such as the mass, size, and surface densities of the clouds are tabulated. The molecular clouds in the Perseus Arm are about 30-50 times more massive, and 4-6 times larger than the clouds in the Local Arm. This result, however, is likely to be biased by distance selection effects. The surface densities of the clouds are enhanced in the Perseus Arm, with an average value of ~100M_{sun}_/pc^2^. Here. we select the 40 most extended (>0.35arcdeg^2^) molecular clouds from the ^12^CO catalog to build the H_2_ column density probability distribution function (N-PDF). Some 78% of the N-PDFs of the selected molecular clouds are well fitted with log-normal functions with only small deviations at high densities, corresponding to star-forming regions with scales of ~1-5pc in the Local Arm, and ~5-10pc in the Perseus Arm. About 18% of the selected molecular clouds have power-law N-PDFs at high densities. In these molecular clouds, the majority of the regions fitted with the power law correspond to molecular clumps at sizes of ~1pc, or filaments at widths of ~1pc.
