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3251. Convective blueshifts for solar-type stars
ID:
ivo://CDS.VizieR/J/A+A/654/A168
Title:
Convective blueshifts for solar-type stars
Short Name:
J/A+A/654/A168
Date:
22 Feb 2022
Publisher:
CDS
Description:
The detection of earth-mass exoplanets in the habitable zone around solar-mass stars using the radial velocity technique requires extremely high- precision of the order of 10cm/s. This puts the required noise floor below the intrinsic variability of even relatively inactive stars, like the Sun. One such variable is convective blueshift varying temporally, spatially and between spectral lines. We develop a novel approach to measure convective blueshift and determine the strength of convective blueshift for 810 stars observed by the HARPS spectrograph, spanning spectral types from late-F, G, K to early-M. We derive a model to infer blueshift velocity for lines of any depth in later-type stars of any effective temperature. Using a custom list of spectral lines, covering a wide range of absorption depths, we create a model for the line-core shift as a function of line depth, commonly known as the third signature of granulation. For this we utilize an extremely high-resolution solar spectrum (R~1.000.000) to empirically account for the non-linear nature of the third signature. The solar third signature is then scaled to all 810 stars. Through this we obtain a measure of the convective blueshift relative to the Sun as a function of stellar effective temperature. We confirm the general correlation of increasing convective blueshift with effective temperature and establish a tight, cubic relation between the two that strongly increases for stars above ~5800K. For stars between ~4100K and ~4700K we show for the first time a plateau in convective shift and a possible onset of a plateau for stars above 6000K. Stars below ~4000K show neither blue or red shift. We provide a table listing expected blueshift velocities for each spectral subtype in the data set to quickly access the intrinsic noise floor through convective blueshift for the RV technique.
3252. CO observation of isolated galaxies
ID:
ivo://CDS.VizieR/J/A+A/411/381
Title:
CO observation of isolated galaxies
Short Name:
J/A+A/411/381
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ^12^CO(J=1-0) line observations of 99 galaxies obtained with the SEST 15m, the Kitt Peak 12m and the IRAM 30m telescopes. The target galaxies were selected from the catalogue of isolated galaxies of Karachentseva (1973, Cat. <VII/82>). These data are thus representative of the CO properties of isolated late-type galaxies. All objects were observed in their central position, those with large angular sizes were mapped. These new measurements are used to estimate the molecular gas mass of the target galaxies. The molecular gas is on average ~18% of the atomic gas mass.
3253. CO observations in giant molecular clouds of M33
ID:
ivo://CDS.VizieR/J/ApJ/761/37
Title:
CO observations in giant molecular clouds of M33
Short Name:
J/ApJ/761/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a giant molecular cloud (GMC) catalog of M33 (NGC598), containing 71 GMCs in total, based on wide-field and high-sensitivity CO(J=3-2) observations with a spatial resolution of 100pc using the ASTE 10m telescope. Employing archival optical data, we identify 75 young stellar groups (YSGs) from the excess of the surface stellar density, and estimate their ages by comparing with stellar evolution models. A spatial comparison among the GMCs, YSGs, and H II regions enable us to classify GMCs into four categories: Type A, showing no sign of massive star formation (SF); Type B, being associated only with H II regions; Type C, with both H II regions and <10Myr old YSGs; and Type D, with both H II regions and 10-30Myr YSGs. Out of 65 GMCs (discarding those at the edges of the observed fields), 1 (1%), 13 (20%), 29 (45%), and 22 (34%) are Types A, B, C, and D, respectively. We interpret these categories as stages in a GMC evolutionary sequence. Assuming that the timescale for each evolutionary stage is proportional to the number of GMCs, the lifetime of a GMC with a mass >10^5^M_{sun}_ is estimated to be 20-40Myr. In addition, we find that the dense gas fraction as traced by the CO(J=3-2)/CO(J=1-0) ratio is enhanced around SF regions. This confirms a scenario where dense gas is preferentially formed around previously generated stars, and will be the fuel for the next stellar generation. In this way, massive SF gradually propagates in a GMC until gas is exhausted.
3254. CO observations in NGC 1365
ID:
ivo://CDS.VizieR/J/A+A/295/585
Title:
CO observations in NGC 1365
Short Name:
J/A+A/295/585
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of the J=1-0 and J=2-1 CO observations are presented
3255. CO observations in spirals
ID:
ivo://CDS.VizieR/J/A+AS/118/47
Title:
CO observations in spirals
Short Name:
J/A+AS/118/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 1300{mu}m continuum observations and measurements of the CO (1-0) and (2-1) emission from the inner regions of 98 normal galaxies. The spatial resolution ranges from 11arcsec to 45arcsec. The sources come from a complete FIR selected sample of 138 inactive spirals with an optical diameter D_25_<=180arcsec.
3256. CO observations of clouds in IC 1396 region
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
3257. CO Observations of Galaxies
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.
3258. CO observations of LMC Giant Molecular clouds
ID:
ivo://CDS.VizieR/J/ApJS/178/56
Title:
CO observations of LMC Giant Molecular clouds
Short Name:
J/ApJS/178/56
Date:
21 Oct 2021
Publisher:
CDS
Description:
The second survey of the molecular clouds in the Large Magellanic Cloud in ^12^CO(J=1-0) was carried out by NANTEN. The sensitivity of this survey is twice as high as that of the previous NANTEN survey, leading to a detection of molecular clouds with M_CO_>~2x10^4^solMass. We identified 272 molecular clouds, 230 of which are detected at three or more observed positions. We derived the physical properties, such as size, line width, and virial mass, of the 164 GMCs (Giant Molecular clouds) that have an extent more than the beam size of NANTEN in both the major and minor axes.
3259. CO observations of LMC molecular clouds (MAGMA).
ID:
ivo://CDS.VizieR/J/ApJS/197/16
Title:
CO observations of LMC molecular clouds (MAGMA).
Short Name:
J/ApJS/197/16
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the properties of an extensive sample of molecular clouds in the Large Magellanic Cloud (LMC) mapped at 11pc resolution in the CO(1-0) line. Targets were chosen based on a limiting CO flux and peak brightness as measured by the NANTEN survey. The observations were conducted with the ATNF Mopra Telescope as part of the Magellanic Mopra Assessment. We identify clouds as regions of connected CO emission and find that the distributions of cloud sizes, fluxes, and masses are sensitive to the choice of decomposition parameters.
3260. CO observations of major merger pairs at z=0
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.

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