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101. Compact clouds in a sensitive GBT HI survey
ID:
ivo://CDS.VizieR/J/ApJ/855/33
Title:
Compact clouds in a sensitive GBT HI survey
Short Name:
J/ApJ/855/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a new sensitive survey of neutral hydrogen above and below the Galactic Center with the Green Bank Telescope. The observations extend up to Galactic latitude |b|<10{deg} with an effective angular resolution of 9.5' and an average rms brightness temperature noise of 40mK in a 1km/s channel. The survey reveals the existence of a population of anomalous high-velocity clouds extending up to heights of about 1.5kpc from the Galactic plane and showing no signature of Galactic rotation. These clouds have local standard of rest velocities |V_LSR_|<~360km/s, and assuming a Galactic Center origin, they have sizes of a few tens of parsec and neutral hydrogen masses spanning 10-10^5^M_{sun}_. Accounting for selection effects, the cloud population is symmetric in longitude, latitude, and VLSR. We model the cloud kinematics in terms of an outflow expanding from the Galactic Center and find the population consistent with being material moving with radial velocity V_w_~330km/s distributed throughout a bicone with opening angle {alpha}>140{deg}. This simple model implies an outflow luminosity L_w_>3x10^40^erg/s over the past 10Myr, consistent with star formation feedback in the inner region of the Milky Way, with a cold gas mass-loss rate <~0.1M_{sun}_/yr. These clouds may represent the cold gas component accelerated in the nuclear wind driven by our Galaxy, although some of the derived properties challenge current theoretical models of the entrainment process.
102. Compact H I clouds from the GALFA-H I survey
ID:
ivo://CDS.VizieR/J/ApJ/722/395
Title:
Compact H I clouds from the GALFA-H I survey
Short Name:
J/ApJ/722/395
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic Arecibo L-band Feed Array H I (GALFA-H I) survey is mapping the entire Arecibo sky at 21 cm, over a velocity range of -700 to +700 km/s (LSR), at a velocity resolution of 0.18 km/s, and a spatial resolution of 3.5 arcmin. The unprecedented resolution and sensitivity of the GALFA-H I survey have resulted in the detection of numerous isolated, very compact H I clouds at low Galactic velocities, which are distinctly separated from the H I disk emission. In the limited area of ~4600 deg^2^ surveyed so far, we have detected 96 such compact clouds. The detected clouds are cold with a median T_k,max_ (the kinetic temperature in the case in which there is no non-thermal broadening) of 300 K. Moreover, these clouds are quite compact and faint, with median values of 5 arcmin in angular size, 0.75 K in peak brightness temperature, and 5x10^18^/cm2 in H I column density. Most of the clouds deviate from Galactic rotation at the 20-30 km/s level, and a significant fraction show evidence for a multiphase medium and velocity gradients. No counterparts for these clouds were found in other wave bands. From the modeling of spatial and velocity distributions of the whole compact cloud population, we find that the bulk of the compact clouds are related to the Galactic disk, and their distances are likely to be in the range of 0.1 to a few kpc. We discuss various possible scenarios for the formation and maintenance of this cloud population and its significance for Galactic interstellar medium studies.
103. Compact high-velocity cloud photometry catalog
ID:
ivo://CDS.VizieR/J/ApJ/623/181
Title:
Compact high-velocity cloud photometry catalog
Short Name:
J/ApJ/623/181
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of a photometric search for giant stars associated with the cores of four high-velocity clouds (HVCs) - two of which are compact HVCs - using the Las Campanas du Pont 2.5m and Cerro Tololo Blanco 4m telescopes in combination with a system of filters (Washington M, T_2_ + DDO51) useful for identifying low surface gravity, evolved stars.
104. Complete sample of Galactic clump properties
ID:
ivo://CDS.VizieR/J/MNRAS/473/1059
Title:
Complete sample of Galactic clump properties
Short Name:
J/MNRAS/473/1059
Date:
21 Oct 2021
Publisher:
CDS
Description:
The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) is an unbiased 870um submillimetre survey of the inner Galactic plane (|l|<60{deg} with |b|<1.5{deg}). It is the largest and most sensitive ground-based submillimetre wavelength Galactic survey to date and has provided a large and systematic inventory of all massive, dense clumps in the Galaxy (>=1000M_{sun}_ at a heliocentric distance of 20kpc) and includes representative samples of all of the earliest embedded stages of high-mass star formation. Here, we present the first detailed census of the properties (velocities, distances, luminosities and masses) and spatial distribution of a complete sample of ~8000 dense clumps located in the Galactic disc (5{deg}<|l|<60{deg}). We derive highly reliable velocities and distances to ~97 per cent of the sample and use mid- and far-infrared survey data to develop an evolutionary classification scheme that we apply to the whole sample. Comparing the evolutionary subsamples reveals trends for increasing dust temperatures, luminosities and linewidths as a function of evolution indicating that the feedback from the embedded protoclusters is having a significant impact on the structure and dynamics of their natal clumps. We find that the vast majority of the detected clumps are capable of forming a massive star and 88 per cent are already associated with star formation at some level. We find the clump mass to be independent of evolution suggesting that the clumps form with the majority of their mass in situ. We estimate the statistical lifetime of the quiescent stage to be ~5x10^4^yr for clump masses >1000M_{sun}_ decreasing to ~1x10^4^yr for clump masses >10000M_{sun}_. We find a strong correlation between the fraction of clumps associated with massive stars and peak column density. The fraction is initially small at low column densities, but reaching 100 per cent for column densities above 10^23^cm^x2^; there are no clumps with column densities above this value that are not already associated with massive star formation. All of the evidence is consistent with a dynamic view of star formation wherein the clumps form rapidly and are initially very unstable so that star formation quickly ensues.
105. 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.
106. 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.
107. 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.
108. CO 3-2 observations of outflows in W5
ID:
ivo://CDS.VizieR/J/MNRAS/418/2121
Title:
CO 3-2 observations of outflows in W5
Short Name:
J/MNRAS/418/2121
Date:
21 Oct 2021
Publisher:
CDS
Description:
New James Clerk Maxwell Telescope (JCMT) HARP CO 3-2 observations of the W5 star forming complex are presented, totalling an area of ~12000-arcmin^2^ with sensitivity better than 0.1K per 0.4km/s channel. We discovered 55 CO outflow candidates, of which 40 are associated with W5 and 15 are more distant than the Perseus arm.
109. CO observations of YSOs in NGC 1333
ID:
ivo://CDS.VizieR/J/ApJ/774/22
Title:
CO observations of YSOs in NGC 1333
Short Name:
J/ApJ/774/22
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present observations of outflows in the star-forming region NGC 1333 using the Combined Array for Research in Millimeter-Wave Astronomy (CARMA). We combined the ^12^CO and ^13^CO (1-0) CARMA mosaics with data from the 14m Five College Radio Astronomy Observatory to probe the central, most dense, and active region of this protostellar cluster at scales from 5" to 7' (or 1000AU to 0.5pc at a distance of 235pc). We map and identify ^12^CO outflows, and along with ^13^CO data we estimate their mass, momentum, and energy. Within the 7'x7' map, the 5" resolution allows for a detailed study of morphology and kinematics of outflows and outflow candidates, some of which were previously confused with other outflow emission in the region. In total, we identify 22 outflow lobes, as well as 9 dense circumstellar envelopes marked by continuum emission, of which 6 drive outflows. We calculate a total outflow mass, momentum, and energy within the mapped region of 6M_{sun}_, 19M_{sun}_ km/s, and 7x10^44^erg, respectively. Within this same region, we compare outflow kinematics with turbulence and gravitational energy, and we suggest that outflows are likely important agents for the maintenance of turbulence in this region. In the earliest stages of star formation, outflows do not yet contribute enough energy to totally disrupt the clustered region where most star formation is happening, but have the potential to do so as the protostellar sources evolve.
110. CO obs. of MCs in the Extreme Outer Galaxy region
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.

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