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3391. CO survey of molecular clouds. IV. NGC 1333
ID:
ivo://CDS.VizieR/J/ApJS/214/7
Title:
CO survey of molecular clouds. IV. NGC 1333
Short Name:
J/ApJS/214/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
We mapped the NGC 1333 section of the Perseus Molecular Cloud in the J=2-1 emission lines of ^12^CO and ^13^CO over a 50'x60' region (3.4x4.1pc at the cloud distance of 235pc), using the Arizona Radio Observatory Heinrich Hertz Submillimeter Telescope. The angular resolution is 38" (0.04pc) and velocity resolution is 0.3km/s. We compare our velocity moment maps with known positions of young stellar objects (YSOs) and (sub)millimeter dust continuum emission. The CO emission is brightest at the center of the cluster of YSOs, but is detected over the full extent of the mapped region at >=10xrms. The morphology of the CO channel maps shows a kinematically complex structure, with many elongated features extending from the YSO cluster outward by ~1pc. One notable feature appears as a narrow serpentine structure that curves and doubles back, with a total length of ~3pc. The ^13^CO velocity channel maps show evidence for many low-density cavities surrounded by partial shell-like structures, consistent with previous studies. Maps of the velocity moments show localized effects of bipolar outflows from embedded YSOs, as well as a large-scale velocity gradient around the central core of YSOs, suggestive of large-scale turbulent cloud motions determining the location of current star formation. The CO/^13^CO intensity ratios show the distribution of the CO opacity, which exhibits a complex kinematic structure. Identified YSOs are located mainly at the positions of greatest CO opacity.
3392. 13CO survey of Mon & CMa molecular clouds
ID:
ivo://CDS.VizieR/J/PASJ/56/313
Title:
13CO survey of Mon & CMa molecular clouds
Short Name:
J/PASJ/56/313
Date:
21 Oct 2021
Publisher:
CDS
Description:
Through a large-scale 13^CO (J=1-0) survey toward a region in Monoceros and Canis Major, we have identified in total 115 clouds.
3393. CO survey of spirals in Coma supercluster
ID:
ivo://CDS.VizieR/J/A+AS/116/193
Title:
CO survey of spirals in Coma supercluster
Short Name:
J/A+AS/116/193
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present observations of the ^12^CO(J=1-0) line at 2.6mm of 65 galaxies located in the Coma supercluster region: 33 actually belong to the Coma supercluster while 32 are either foreground or background objects. These data have been obtained using the NRAO 12m telescope at Kitt Peak (United States), and for four galaxies, using the IRAM 30m telescope at Pico Veleta (Spain). Out of these 65 galaxies, 54 had never been observed in the CO(1-0) line; 49 have been detected by us, of which 37 are new detections. We give molecular gas masses deduced from the CO line integrated intensities, and upper limits for the 16 undetected objects, computed with a Galactic conversion factor N(H_2_)=2.3x10^20^I(CO) and H_0_=75km/s/Mpc.
3394. CO survey of the CMa OB1 complex
ID:
ivo://CDS.VizieR/J/ApJS/252/20
Title:
CO survey of the CMa OB1 complex
Short Name:
J/ApJS/252/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the Purple Mountain Observatory 13.7m millimeter telescope at Delingha in China, we have conducted a large-scale simultaneous survey of ^12^CO, ^13^CO, and C^18^O (J=1-0) toward the CMa OB1 complex with a sky coverage of 16.5deg^2^ (221.5{deg}<=l<=227{deg}, -2.5{deg}<=b<=0.5{deg}). Emission from the CMa OB1 complex is found in the range 7km/s<=V_LSR_<=25km/s. The large-scale structure, physical properties, and chemical abundances of the molecular clouds are presented. A total of 83 C^18^O molecular clumps are identified with the GaussClumps algorithm within the mapped region. We find that 94% of these C18O molecular clumps are gravitationally bound. The relationship between their size and mass indicates that none of the C^18^O clumps has the potential to form high-mass stars. Using a semiautomatic IDL algorithm, we newly discover 85 CO outflow candidates in the mapped area, including 23 bipolar outflow candidates. Additionally, a comparative study reveals evidence for a significant variety of physical properties, evolutionary stages, and levels of star formation activity in different subregions of the CMa OB1 complex.
3395. CO survey of W51 molecular cloud
ID:
ivo://CDS.VizieR/J/ApJS/191/232
Title:
CO survey of W51 molecular cloud
Short Name:
J/ApJS/191/232
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 38" resolution maps of the CO and ^13^COJ=2-1 lines in the molecular clouds toward the HII region complex W51. The maps cover a 1.25x1{deg} section of the galactic plane and span +30 to +85km/s (LSR) in velocity. The spectral resolution is ~1.3km/s. The velocity range of the images includes all the gas in the Sagittarius spiral arm. Color figures display the peak line brightness temperature, the velocity-integrated intensity, and 2km/s channel-averaged maps for both isotopologs, and also the CO/^13^COJ=2-1 line intensity ratio as a function of velocity. The CO and ^13^CO line intensity image cubes are made available in standard FITS format as electronically readable tables. We compare our molecular line maps with the 1.1mm continuum image from the BOLOCAM Galactic Plane Survey (BGPS; Aguirre et al. 2011ApJS..192....4A; Rosolowsky et al. 2010, Cat. J/ApJS/188/123). From our ^13^CO image cube, we derive kinematic information for the 99 BGPS sources in the mapped field in the form of Gaussian component fits. The integrated ^13^CO line intensity and the 1.1mm source flux density show only a modest degree of correlation for the 99 sources, likely due to a range of dust and gas physical conditions within the sources. However, the 1.1mm continuum surface brightness and the integrated ^13^CO line intensity for small regions containing single BGPS sources and molecular clouds show very good correlations in many cases.
3396. CO survey toward starless cores
ID:
ivo://CDS.VizieR/J/ApJS/152/81
Title:
CO survey toward starless cores
Short Name:
J/ApJS/152/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
A CO survey is undertaken toward about 80% of the starless cores in the Lee & Myers catalog that can be observed in the northern hemisphere to investigate their general observational properties such as line width and intensity, from which one can deduce their environmental physical conditions. The peak ^12^CO intensity implies a kinetic temperature close to 10K, as is already known, but for some of the cores the kinetic temperature is much higher than 10K, suggesting either that they are not really starless or that they are externally heated. We derive the ratios of peak intensities and line widths for the pairs of ^12^CO and ^13^CO lines and find a value of ~1.7 for both. The linear correlations between them are most likely to be due to clumpy structure. These data are also compared with data sets of CS 2-1 and N_2_H^+^ 1-0 lines tracing high-density regions. It is found that the peak intensity and line width of ^13^CO are roughly correlated with those of CS, suggesting that the outer envelope is kinematically related to the inner dense core. Confirming that the ^12^CO lines seldom exhibit deep self-reversal features, whereas this is not unusual for the CS lines, we propose a heuristic model where the outer part is clumpy, but the inner part has a rather smooth density profile, with a uniform temperature and mean density decreasing outward. We apply three-dimensional radiative transfer calculations to this simple model, demonstrating that the essential observational features of the starless cores are successfully reproduced.
3397. CO Tully-Fisher relation for host galaxies of QSOs
ID:
ivo://CDS.VizieR/J/ApJ/669/821
Title:
CO Tully-Fisher relation for host galaxies of QSOs
Short Name:
J/ApJ/669/821
Date:
21 Oct 2021
Publisher:
CDS
Description:
The integrated line width derived from CO spectroscopy provides a powerful tool to study the internal kinematics of extragalactic objects, including quasars at high redshift, provided that the observed line width can be properly translated to more conventionally used kinematical parameters of galaxies. We show, through the construction of a Ks-band CO Tully-Fisher relation for nearby galaxies spanning a wide range in infrared luminosity, that the CO line width measured at 20% of the peak intensity, when corrected for inclination and other effects, successfully recovers the maximum rotation velocity of the disk. The line width at 50% of the peak intensity performs much more poorly, in large part because CO lines have a wide range of profiles, which are shown to vary systematically with infrared luminosity. We present a practical prescription for converting observed CO line widths into the stellar velocity dispersion of the bulge ({sigma}*) and then apply it to a sample of low-redshift (z<~0.2) and high-redshift (1.4<~z<~6.4) quasars to study their host galaxies.
3398. Coulour-Period relation for Cepheids
ID:
ivo://CDS.VizieR/J/MNRAS/459/1170
Title:
Coulour-Period relation for Cepheids
Short Name:
J/MNRAS/459/1170
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compare mid-infrared (IR) 3.6 and 4.5{mu}m Warm Spitzer observations for Cepheids in the Milky Way and the Large and Small Magellanic Clouds. Using models, we explore in detail the effect of the CO rotation-vibration band-head at 4.6{mu}m on the mid-IR photometry. We confirm the temperature sensitivity of the CO band-head at 4.6{mu}m and find no evidence for an effect at 3.6{mu}m. We compare the ([3.6]-[4.5]) period-colour relations in the MW, LMC and SMC. The slopes of the period-colour relations for the three galaxies are in good agreement, but there is a trend in zero-point with metallicity, with the lowest metallicity Cepheids having redder mid-IR colours. Finally, we present a colour-[Fe/H] relation based on published spectroscopic metallicities. This empirical relation, calibrated to the metallicity system of Genovali et al., demonstrates that the ([3.6]-[4.5]) colour provides a reliable metallicity indicator for Cepheids, with a precision comparable to current spectroscopic determinations.
3399. Counterparts to 1.4GHz sources in ECDF-S
ID:
ivo://CDS.VizieR/J/ApJS/203/15
Title:
Counterparts to 1.4GHz sources in ECDF-S
Short Name:
J/ApJS/203/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study a sample of 883 sources detected in a deep Very Large Array survey at 1.4GHz in the Extended Chandra Deep Field South. This paper focuses on the identification of their optical and infrared (IR) counterparts. We use a likelihood-ratio technique that is particularly useful when dealing with deep optical images to minimize the number of spurious associations. We find a reliable counterpart for 95% of our radio sources. Most of the counterparts (74%) are detected at optical wavelengths, but there is a significant fraction (21%) that are only detectable in the IR. Combining newly acquired optical spectra with data from the literature, we are able to assign a redshift to 81% of the identified radio sources (37% spectroscopic). We also investigate the X-ray properties of the radio sources using the Chandra 4Ms and 250ks observations. In particular, we use a stacking technique to derive the average properties of radio objects undetected in the Chandra images. The results of our analysis are collected in a new catalog containing the position of the optical/IR counterpart, the redshift information, and the X-ray fluxes. It is the deepest multi-wavelength catalog of radio sources, which will be used for future study of this galaxy population.
3400. Counts and spectral indices at 8.44GHz
ID:
ivo://CDS.VizieR/J/ApJ/405/498
Title:
Counts and spectral indices at 8.44GHz
Short Name:
J/ApJ/405/498
Date:
21 Oct 2021
Publisher:
CDS
Description:
We used the VLA to make deep images of two 7x7' fields at 8.44 GHz with 10" resolution. With an rms noise of 3.2 and 5.1 {micro}Jy, respectively, in the two fields, we compiled a catalog of 82 sources. The normalized differential 8.44 GHz counts are similar to those at 1.41 and 4.86 GHz. All show a similarly steep submillijansky slope, which is only somewhat flatter than that expected for a nonevolving Euclidean population ({gamma}=2.5). Microjansky radio sources at 4.86 GHz have been identified with faint blue galaxies (18<~V<~28 mag). We argue that their expected median redshift is about 0.5-0.75. Hence, cosmological evolution may be needed to explain the steep slope of the microjansky counts. The 8.44 GHz counts must converge with slope {gamma}<2.0 below S(8.44)~300 nJy, or they would exceed the available field galaxy counts down to V~28 mag, and they must permanently converge below S(8.44)~20 nJy, or their integrated sky brightness would distort the observed thermal cosmic background radiation spectrum at centimeter wavelengths. The estimated 31.5 GHz sky brightness from nanojansky to jansky levels is <36 {micro}K (3{sigma}). Even if weak radio sources cluster on scales of degrees as faint galaxies do, their anisotropic contribution to the COBE DMR experiment (with 7deg FWHM-beam) would not exceed ~1.2{micro}K.

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