- ID:
- ivo://CDS.VizieR/J/ApJ/761/97
- Title:
- Star Formation in Radio Survey (SFRS): 33GHz obs.
- Short Name:
- J/ApJ/761/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 33GHz photometry of 103 galaxy nuclei and extranuclear star-forming complexes taken with the Green Bank Telescope (GBT) as part of the Star Formation in Radio Survey (SFRS). Among the sources without evidence for an active galactic nucleus, and also having lower frequency radio data, we find a median thermal fraction at 33GHz of {approx}76% with a dispersion of {approx}24%. For all sources resolved on scales <~0.5kpc, the thermal fraction is even larger, being >~90%. This suggests that the rest-frame 33GHz emission provides a sensitive measure of the ionizing photon rate from young star-forming regions, thus making it a robust star formation rate (SFR) indicator. Taking the 33 GHz SFRs as a reference, we investigate other empirical calibrations relying on different combinations of warm 24{mu}m dust, total infrared (IR; 8-1000{mu}m), H{alpha} line, and far-UV continuum emission. The recipes derived here generally agree with others found in the literature, albeit with a large dispersion that most likely stems from a combination of effects. Comparing the 33GHz to total IR flux ratios as a function of the radio spectral index, measured between 1.7 and 33GHz, we find that the ratio increases as the radio spectral index flattens which does not appear to be a distance effect. Consequently, the ratio of non-thermal to total IR emission appears relatively constant, suggesting only moderate variations in the cosmic-ray electron injection spectrum and ratio of synchrotron to total cooling processes among star-forming complexes. Assuming that this trend solely arises from an increase in the thermal fraction sets a maximum on the scatter of the non-thermal spectral indices among the star-forming regions of {sigma}_{alpha}_NT<~0.13.
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- ID:
- ivo://CDS.VizieR/J/ApJ/752/146
- Title:
- Star forming complexes in Galactic WMAP sources
- Short Name:
- J/ApJ/752/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze Spitzer GLIMPSE, Midcourse Space Experiment (MSX), and Wilkinson Microwave Anisotropy Probe (WMAP) images of the Milky Way to identify 8{mu}m and free-free sources in the Galaxy. Seventy-two of the 88 WMAP sources have coverage in the GLIMPSE and MSX surveys suitable for identifying massive star-forming complexes (SFCs). We measure the ionizing luminosity functions of the SFCs and study their role in the turbulent motion of the Galaxy's molecular gas. We find a total Galactic free-free flux f_{nu}_=46177.6Jy; the 72 WMAP sources with full 8{mu}m coverage account for 34263.5Jy (~75%), with both measurements made at {nu}=94GHz (W band). We find a total of 280 SFCs, of which 168 have unique kinematic distances and free-free luminosities. We use a simple model for the radial distribution of star formation to estimate the free-free and ionizing luminosity for the sources lacking distance determinations. The total dust-corrected ionizing luminosity is Q=(2.9+/-0.5)x10^53^photons/s, which implies a Galactic star formation rate of \dot{M}_{star}_=1.2+/-0.2{M}_{sun}_/yr. We present the (ionizing) luminosity function of the SFCs and show that 24 sources emit half the ionizing luminosity of the Galaxy. The SFCs appear as bubbles in GLIMPSE or MSX images; the radial velocities associated with the bubble walls allow us to infer the expansion velocity of the bubbles. We calculate the kinetic luminosity of the bubble expansion and compare it to the turbulent luminosity of the inner molecular disk. SFCs emitting 80% of the total Galactic free-free luminosity produce a kinetic luminosity equal to 65% of the turbulent luminosity in the inner molecular disk. This suggests that the expansion of the bubbles is a major driver of the turbulent motion of the inner Milky Way molecular gas.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A136
- Title:
- Starless core L1521E chemical structure
- Short Name:
- J/A+A/630/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained ~2.5x2.5 arcminute maps toward L1521E using the IRAM-30m telescope in transitions of various species, including C^17^O, CH_3_OH c-C_3_H_2_, CN, SO, H_2_CS, and CH_3_CCH. We derived abundances for the observed species and compared them to those obtained toward L1544. We estimated CO depletion factors using the C^17^O IRAM-30m map, an N(H2) map derived from Herschel/ SPIRE data and a 1.2 mm dust continuum emission map obtained with the IRAM-30m telescope. Similarly to L1544, c-C_3_H_2_ and CH_3_OH peak at different positions. Most species peak toward the c-C_3_H_2_ peak: C_2_S, C_3_S, HCS^+^, HC_3_N, H_2_CS, CH_3_CCH, C^34^S. C^17^O and SO peak close to both the c-C_3_H_2_ and the CH_3_OH peaks. CN and N_2_H^+^ peak close to the Herschel dust peak. We found evidence of CO depletion toward L1521E. The lower limit of the CO depletion factor derived toward the Herschel dust peak is 4.3+/-1.6, which is about a factor of three lower than toward L1544. We derived abundances for several species toward the dust peaks of L1521E and L1544. The abundances of most sulfur-bearing molecules such as C_2_S, HCS^+^, C^34^S, C^33^S, and HCS^+^ are higher toward L1521E than toward L1544 by factors of ~2-20, compared to the abundance of A-CH_3_OH. The abundance of methanol is very similar toward the two cores.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A60
- Title:
- Starless cores CH_3_OH and c-C_3_H_2_ maps
- Short Name:
- J/A+A/643/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spatial distribution of molecules around starless cores is a powerful tool for studying the physics and chemistry governing the earliest stages of star formation. Our aim is to study the chemical differentiation in starless cores to determine the influence of large-scale effects on the spatial distribution of molecules within the cores. Furthermore, we want to put observational constraints on the mechanisms responsible in starless cores for the desorption of methanol from the surface of dust grains where it is efficiently produced. We mapped methanol, CH_3_OH, and cyclopropenylidene, c-C_3_H_2_, with the IRAM 30m telescope in the 3mm band towards six starless cores embedded in different environments, and in different evolutionary stages. Furthermore, we searched for correlations among physical properties of the cores and the methanol distribution. From our maps we can infer that the chemical segregation between CH_3_OH and c-C_3_H_2_ is driven by uneven illumination from the interstellar radiation field (ISRF). The side of the core that is more illuminated has more C atoms in the gas-phase and the formation of carbon-chain molecules like c-C3H2 is enhanced. Instead, on the side that is less exposed to the ISRF the C atoms are mostly locked in carbon monoxide, CO, the precursor of methanol. We conclude that large-scale effects have a direct impact on the chemical segregation that we can observe at core scale. However, the non-thermal mechanisms responsible for the desorption of methanol in starless cores do not show any dependency on the H_2_ column density at the methanol peak.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/928
- Title:
- Starless cores in HCN(J=1-0)
- Short Name:
- J/ApJ/664/928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a survey toward the central regions of 85 starless cores in HCN(J=1-0) to study inward motions in the cores. Sixty-four cores were detected with HCN lines. The infall asymmetry in the HCN spectra is found to be more prevalent, and more prominent than in any other previously used infall tracers such as CS(J=2-1), DCO^+^(J=2-1), and N2H^+^(J=1-0). We have found a close relation between the intensities of the HCN and N2H^+^ lines.
- ID:
- ivo://CDS.VizieR/J/AZh/87/739
- Title:
- Steep and ultra-steep spectra RC sources
- Short Name:
- J/AZh/87/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra (alpha<-0.9, S{prop.to}nu^alpha^) from the "Big Trio" (RATAN-600-VLA-BTA) project, performed with the "Scorpio" spectrograph on the 6-m telescope of the Special Astrophysical Observatory (Russian Academy of Sciences). Redshifts were determined for these objects. We also present several other parameters of the sources, such as their R magnitudes, maximum radio sizes in seconds of arc, flux densities at 500, 1425, and 3940MHz, radio luminosities at 500 and 3940MHz, and morphology. Of the total number of radio galaxies studied, four have redshifts 1<=z<2, three have 2<=z<3, one has 3<=z<4, and one has z=4.51. Thirteen sources have redshifts 0.7<z<1 and 15 have 0.2<z<0.7. Of all the quasars studied, five have redshifts 0.7<z<1, seven have 1<=z<2, four have 2<=z<3, and one has z=3.57. We did not detect any spectral lines for 17 objects.
- ID:
- ivo://CDS.VizieR/J/A+AS/91/337
- Title:
- Steep spectrum radio spectra sources
- Short Name:
- J/A+AS/91/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/V/68A
- Title:
- Stellar Maser Observations
- Short Name:
- V/68A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains about 2958 stellar sources. For the searching of the maser emission of the sources listed, 368 were detected in H2O, 209 in SiO, and 713 in OH. In the catalog, one can find information about the stars including alternate names, the 1950 epoch position, velocity (LSR), spectral type, variability type, and period, as well as the references for both the detections and nondetections for each of the three molecules. In this catalog, Table 1 lists all the sources in right ascension order, Table 2 lists the references for all the maser observations for each source, and Table 3 lists the references in code order, i.e., in chronological order.
- ID:
- ivo://CDS.VizieR/J/AZh/77/3
- Title:
- Studies of Bright Steep-Spectrum Radio Sources
- Short Name:
- J/AZh/77/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of studies of bright radio sources in the constellation Cetus are presented. More than 50% of the sources have radio spectral indices steeper than 0.9. Optical identifications have been determined for 35 sources. A large fraction of the radio sources are identified with weak blue galaxies. Given their spectral indices, it is likely that these objects have redshift z=0.4-1.0. More than 20% of the steep-spectrum sources do not have optical identifications and appear to be weak galaxies with z>2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3060
- Title:
- Subaru/XMM Deep Field radio imaging. III.
- Short Name:
- J/MNRAS/421/3060
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic and 11-band photometric redshifts for galaxies in the 100-uJy Subaru/XMM-Newton Deep Field radio source sample. We find good agreement between our redshift distribution and that predicted by the Square Kilometre Array (SKA) Simulated Skies project. We find no correlation between K-band magnitude and radio flux, but show that sources with 1.4-GHz flux densities below ~1mJy are fainter in the near-infrared than brighter radio sources at the same redshift, and we discuss the implications of this result for spectroscopically incomplete samples where the K-z relation has been used to estimate redshifts. We use the infrared-radio correlation to separate our sample into radio-loud and radio-quiet objects and show that only radio-loud hosts have spectral energy distributions consistent with predominantly old stellar populations, although the fraction of objects displaying such properties is a decreasing function of radio luminosity.
