- ID:
- ivo://CDS.VizieR/J/A+A/594/A117
- Title:
- CO-H2 and complex organic molecules in TMC-1C
- Short Name:
- J/A+A/594/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Almost 200 different species have been detected in the interstellar medium (ISM) during the last decades, revealing not only simple species but complex molecules with more than 6 atoms. Other exotic compounds, like the weakly-bound dimer (H_2_)_2_, have also been detected in astronomical sources like Jupiter. We aim at detecting for the first time the CO-H_2_ van der Waals complex in the ISM, which if detected can be a sensitive indicator for low temperatures. We use the IRAM30m telescope, located in Pico Veleta (Spain), to search for the CO-H_2_ complex in a cold, dense core in TMC-1C (with a temperature of 10K). All the brightest CO-H_2_ transitions in the 3mm (80-110GHz) band have been observed with a spectral resolution of 0.5-0.7km/s, reaching a rms noise level of 2mK. The simultaneous observation of a broad frequency band, 16GHz, has allowed us to conduct a serendipitous spectral line survey. No lines belonging to the CO-H_2_ complex have been detected. We have set up a new, more stringent upper limit for its abundance to be [CO-H_2_]/[CO]=5x10^-6^, while we expect the abundance of the complex to be in the range 10^-8^-10^-3^. The spectral line survey has allowed us to detect 75 lines associated with 41 different species (including isotopologues). We detect a number of complex organic species, e.g. methyl cyanide (CH_3_CN), methanol (CH_3_OH), propyne (CH_3_CCH) and ketene (CH_2_CO), associated with cold gas (excitation temperatures about 7K), confirming the presence of these complex species not only in warm objects but also in cold regimes.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/686/948
- Title:
- CO in extragalactic giant molecular clouds
- Short Name:
- J/ApJ/686/948
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use high spatial resolution observations of CO to systematically measure the resolved size-line width, luminosity-line width, luminosity-size, and mass-luminosity relations of GMCs in a variety of extragalactic systems. Although the data are heterogeneous, we analyze them in a consistent manner to remove the biases introduced by limited sensitivity and resolution, thus obtaining reliable sizes, velocity dispersions, and luminosities. We compare the results obtained in dwarf galaxies with those from the Local Group spiral galaxies. We find that extragalactic GMC properties measured across a wide range of environments are very much compatible with those in the Galaxy. The property that shows the largest variability is their resolved brightness temperature, although even that is similar to the average Galactic value in most sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/181/255
- Title:
- CO in Galactic HII regions
- Short Name:
- J/ApJS/181/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the molecular properties for a sample of 301 Galactic HII regions including 123 ultra compact (UC), 105 compact, and 73 diffuse nebulae. We analyze all sources within the BU-FCRAO Galactic Ring Survey (GRS) of ^13^CO emission known to be HII regions based upon the presence of radio continuum and cm-wavelength radio recombination line emission. Unlike all previous large area coverage ^13^CO surveys, the GRS is fully sampled in angle and yet covers ~75deg^2^ of the Inner Galaxy. The angular resolution of the GRS (46") allows us to associate molecular gas with HII regions without ambiguity and to investigate the physical properties of this molecular gas. We find clear CO/HII morphological associations in position and velocity for ~80% of the nebular sample. Compact HII region molecular gas clouds are on average larger than UC clouds: 2.2' compared to 1.7'.
- ID:
- ivo://CDS.VizieR/J/ApJS/141/157
- Title:
- CO (J=1-0) data of cold IRAS sources
- Short Name:
- J/ApJS/141/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conducted a large-scale survey for the cold infrared sources along the northern Galactic plane in the CO (J=1-0) line. There are 1912 IRAS sources selected on the basis of their color indices over the 12, 25, and 60{mu}m wave bands and their association with regions of recent star formation. A quick single-point survey was made toward all of the sources, which results in a detection of 1331 sources with significant CO emission above the detection limit of 0.7K, inferring a CO detection rate of 70%. Located over a wide range of the Galactocentric distances, the CO sources show high concentration toward the spiral arms. Among the detected sources, there are 351 sources found to have high-velocity CO wing emission. A search for the latest catalog of high-velocity CO flows (HVFs) from young stellar objects indicates that 289 sources are beyond the present lists of HVFs. These high-velocity wing sources provide us with a comprehensive database for the study of HVFs from young stellar objects. Using the known outflow sources as an effective indicator, we found that the detection rate for high-velocity wings during the quick survey is 62%, moderately sensitive in searching for new outflow sources. The CO detection rate of the IRAS sources, combined with the ratio of high-velocity wing, suggests that 41% of the CO sources are undergoing the HVF phase. In this paper, the CO spectra are presented along with the preliminary statistics of the data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/485/2417
- Title:
- CO J=2-1 NOEMA observations of mu Cep
- Short Name:
- J/MNRAS/485/2417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Red supergiant stars are surrounded by a gaseous and dusty circumstellar environment created by their mass loss which spreads heavy elements into the interstellar medium. The structure and the dynamics of this envelope are crucial to understand the processes driving the red supergiant mass loss and the shaping of the pre-supernova ejecta. We have observed the emission from the CO J=2-1 line from the red supergiant star {mu} Cep with the NOEMA interferometer. In the line the synthesized beam was 0.92x0.72-arcsec (590x462au at 641pc). The continuum map shows only the unresolved contribution of the free-free emission of the star chromosphere. The continuum-subtracted channel maps reveal a very inhomogeneous and clumpy circumstellar environment. In particular, we detected a bright CO clump, as bright as the central source in the line, at 1.80-arcsec south-west from the star, in the blue channel maps. After a deprojection of the radial velocity assuming two different constant wind velocities, the observations were modelled using the 3D radiative transfer code LIME to derive the characteristics of the different structures. We determine that the gaseous clumps observed around {mu} Cep are responsible for a mass loss rate of (4.9+/-1.0)x10^-7^M_[sun}_/yr, in addition to a spatially unresolved wind component with an estimated mass-loss rate of 2.0x10^-6^M_[sun}_/yr. Therefore, the clumps have a significant role in {mu} Cep's mass loss (>=25%). We cannot exclude that the unresolved central outflow may be made of smaller unresolved clumps.
- 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.
307. COLD GASS survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/32
- Title:
- COLD GASS survey
- Short Name:
- J/MNRAS/415/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We are conducting COLD GASS, a legacy survey for molecular gas in nearby galaxies. Using the IRAM 30-m telescope, we measure the CO(1-0) line in a sample of ~350 nearby (D_I_~=100-200Mpc), massive galaxies (log(M*/M_{sun}_)>10.0). The sample is selected purely according to stellar mass, and therefore provides an unbiased view of molecular gas in these systems. By combining the IRAM data with Sloan Digital Sky Survey (SDSS) photometry and spectroscopy, GALEX imaging and high-quality Arecibo HI data, we investigate the partition of condensed baryons between stars, atomic gas and molecular gas in 0.1-10L* galaxies. In this paper, we present CO luminosities and molecular hydrogen masses for the first 222 galaxies. Description: To overcome this issue, the GALEX Arecibo SDSS Survey (GASS; Catinella et al. 2010, Cat. J/MNRAS/403/683) was designed to measure the neutral hydrogen content for a large, unbiased sample of ~1000 massive galaxies (M*>10^10^M_{sun}_), via longer pointed observations. GASS is a large programme currently under way at the Arecibo 305-m telescope, and is producing some of the first unbiased atomic gas scaling relations in the nearby Universe (Catinella et al. 2010, Cat. J/MNRAS/403/683; Schiminovich et al., 2010MNRAS.408..919S; Fabello et al., 2011MNRAS.411..993F). We are in the process of constructing a CO Legacy Data base for the GASS survey (COLD GASS), measuring the molecular gas content of a significant subsample of the GASS galaxies. We will then be able to quantify the link between atomic gas, molecular gas and stars in these systems.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/2601
- Title:
- CO lines in luminous IR galaxies
- Short Name:
- J/MNRAS/426/2601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from a large molecular line survey of luminous infrared galaxies (LIRGs; L_IR_>~10^11^L_{sun}_) in the local Universe (z<=0.1), conducted during the last decade with the James Clerk Maxwell Telescope and the IRAM 30-m telescope. This work presents the CO and ^13^CO line data for 36 galaxies, further augmented by multi-J total CO line luminosities available for other infrared (IR) bright galaxies from the literature. This yields a combined sample of N=70 galaxies with the star formation (SF) powered fraction of their IR luminosities spanning L^(*)^IR_~10^10^-2x10^12^)L_{sun}_ and a wide range of morphologies.
- ID:
- ivo://CDS.VizieR/J/AJ/137/4436
- Title:
- Coma cluster VLA survey
- Short Name:
- J/AJ/137/4436
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep 1.4GHz Very Large Array radio continuum observations of two ~0.5{deg}^2^ fields in the Coma cluster of galaxies. The two fields, "Coma 1" and "Coma 3", correspond to the cluster core and southwest infall region and were selected on account of abundant preexisting multiwavelength data. In their most sensitive regions the radio data reach 22uJy rms per 4.4" beam, sufficient to detect (at 5{sigma}) Coma member galaxies with L_1.4GHz_=1.3x10^20^W/Hz. The full catalog of radio detections is presented herein and consists of 1030 sources detected at >=5{sigma}, 628 of which are within the combined Coma 1 and Coma 3 area. We also provide optical identifications of the radio sources using data from the Sloan Digital Sky Survey. The depth of the radio observations allows us to detect active galactic nucleus in cluster elliptical galaxies with M_r_<-20.5 (AB magnitudes), including radio detections for all cluster ellipticals with M_r_<-21.8. At fainter optical magnitudes (-20.5<M_r_~<-19), the radio sources are associated with star-forming galaxies with star formation rates as low as 0.1M_{sun}_/yr.
- ID:
- ivo://CDS.VizieR/J/A+A/499/175
- Title:
- ^12^CO(2-1) map of NGC 2264-C
- Short Name:
- J/A+A/499/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The role played by protostellar feedback in clustered star formation is still a matter of debate. In particular, protostellar outflows have been proposed as a source of turbulence in cluster-forming clumps, which may provide support against global collapse for several free-fall times. Here, we seek to test the above hypothesis in the case of the well-documented NGC 2264-C protocluster, by quantifying the amount of turbulence and support injected in the surrounding medium by protostellar outflows. Using the HERA heterodyne array on the IRAM 30m telescope, we carried out an extensive mapping of NGC 2264-C in the three molecular line transitions ^12^CO(2-1), ^13^CO(2-1), and C^18^O(2-1). We found widespread high-velocity 12 CO emission, testifying to the presence of eleven outflow lobes, closely linked to the compact millimeter continuum sources previously detected in the protocluster. We carried out a detailed analysis of the dynamical parameters of these outflows, including a quantitative evaluation of the overall momentum flux injected in the cluster-forming clump. These dynamical parameters were compared to the gravitational and turbulent properties of the clump. We show that the population of protostellar outflows identified in NGC 2264-C is likely to contribute a significant fraction of the observed turbulence but cannot efficiently support the protocluster against global collapse. Gravity appears to largely dominate the dynamics of the NGC 2264-C clump at the present time ; however it is possible that an increase in the star formation rate during the later evolution of the protocluster will trigger enough outflows to finally halt the contraction of the cloud.
