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301. M100 (NGC4321) HII region IRAC photometry
ID:
ivo://CDS.VizieR/J/A+A/553/A54
Title:
M100 (NGC4321) HII region IRAC photometry
Short Name:
J/A+A/553/A54
Date:
21 Oct 2021
Publisher:
CDS
Description:
We systematically study the relations between the H{alpha} luminosity and the near-IR luminosity and temperature of a set of selected HII regions in the disc of M100. By using the technique of cross-reference between the optical H{alpha} image (the catalogue of HII regions in M100 and the Spitzer IRAC images, we locate the selected HII regions in the IRAC image frames. By using the chi-squared non-linear fitting technique, we estimate the IRAC-3-band colour temperature T_col(IRAC)_ of selected HII regions, and calculate their near-IR luminosities.
302. Molecular clouds associated with HII regions
ID:
ivo://CDS.VizieR/J/AJ/141/123
Title:
Molecular clouds associated with HII regions
Short Name:
J/AJ/141/123
Date:
21 Oct 2021
Publisher:
CDS
Description:
The properties of molecular clouds associated with 10 HII regions were studied using CO observations. We identified 142 dense clumps within our sample and found that our sources are divided into two categories: those with clumps that show a power-law size-line-width relation (Type I) and those that do not show any relation (Type II). The clumps in the Type I sources have larger power-law indices than found in previous studies. The clumps in the Type II sources have larger line widths than do the clumps in the Type I sources.
303. Molecular clouds in 8<l<38, -1<b<+1
ID:
ivo://CDS.VizieR/J/other/AcApS/18.302
Title:
Molecular clouds in 8<l<38, -1<b<+1
Short Name:
J/other/AcApS/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
A systematic comparison between molecular clouds in different evolutionary stages and processes of star formation is made over the range of 8{deg} to 38{deg} in Galactic longitude and -1{deg} to +1{deg} in Galactic latitude by using the Massachusetts-Stony Brook Survey data of ^12^CO in the Galactic plane (HPFW=47") and the IRAS Infrared Sky Survey image data (1.5' per pixel). This region is divided into thirty subregions. Then, the space distribution of CO(1-0) emission and the corresponding infrared intensity at 60ymis obtained for each subregion, and the contours of infrared color temperatures and optical depths of molecular cloud complexes in the corresponding regions are calculated and derived. Moreover, the catalogs of the IRAS infrared point sources and HII regions are used. Thus, molecular clouds in different evolutionary stages are identified and divided into four groups ranging from young clouds to evolved clouds, and their main characteristics and relations to the processes of star formation are analysed. The Galatic-longitude distributions of ultracompact HII regions and candidate protostars as well as the ratio between HII region-molecular cloud and candidate protostar-molecular cloud associations are analysed statistically. The results indicate that star formation activities are currently still going on in our Galaxy.
304. Molecular clouds in southern HII regions
ID:
ivo://CDS.VizieR/J/PASJ/51/791
Title:
Molecular clouds in southern HII regions
Short Name:
J/PASJ/51/791
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have carried out extensive ^13^CO(J=1-0) observations toward 23 southern H II regions associated with bright-rimmed clouds. In total, 95 molecular clouds have been identified to be associated with the H II regions. Among the 95, 57 clouds are found to be associated with 204 IRAS point sources which are candidates for young stellar objects. There is a significant increase of star-formation efficiency on the side facing to the H II regions; the luminosity-to-mass ratio, defined as the ratio of the stellar luminosity to the molecular cloud mass, is higher by an order of magnitude on the near side of the H II regions than that on the. far side. This indicates that molecular gas facing to the H II regions is more actively forming massive stars whose luminosity is ~>10^3^L_{sun}_. In addition, the number density of the IRAS point sources increases by a factor of 2 on the near side of the H II regions compared with on the far side. These results strongly suggest that the active formation of massive stars on the near side of the H II regions is due to the effects of the H II regions, such as the compression of molecular material by the ionization/shock fronts. For the whole Galaxy, we estimate that the present star-formation rate under such effects is at least 0.2-0.4M_{sun}_/yr, corresponding to a few 10% by mass.
305. Molecular clouds in the LMC by NANTEN. II.
ID:
ivo://CDS.VizieR/J/ApJS/184/1
Title:
Molecular clouds in the LMC by NANTEN. II.
Short Name:
J/ApJS/184/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We studied star formation activities in the molecular clouds in the Large Magellanic Cloud. We have utilized the second catalog of 272 molecular clouds obtained by NANTEN (4m radio telescope of Nagoya University at Las Campanas Observatory, Chile) to compare the cloud distribution with signatures of massive star formation including stellar clusters, and optical and radio HII regions. We find that the molecular clouds are classified into three types according to the activities of massive star formation: Type I shows no signature of massive star formation; Type II is associated with relatively small HII region(s); and Type III with both HII region(s) and young stellar cluster(s). The radio continuum sources were used to confirm that Type I giant molecular clouds (GMCs) do not host optically hidden HII regions. These signatures of massive star formation show a good spatial correlation with the molecular clouds in the sense that they are located within ~100pc of the molecular clouds.
306. Molecular gas associated with IRAS 10361-5830
ID:
ivo://CDS.VizieR/J/A+A/570/A109
Title:
Molecular gas associated with IRAS 10361-5830
Short Name:
J/A+A/570/A109
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the distribution of the molecular gas and dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped HII region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and of investigating the evolutionary state of the young stellar objects identified there.
307. Molecular ion abundances in diffuse ISM
ID:
ivo://CDS.VizieR/J/A+A/622/A26
Title:
Molecular ion abundances in diffuse ISM
Short Name:
J/A+A/622/A26
Date:
21 Oct 2021
Publisher:
CDS
Description:
The transition between atomic and molecular hydrogen is associated with important changes in the structure of interstellar clouds, and marks the beginning of interstellar chemistry. Most molecular ions are rapidly formed (in ion-molecule reactions) and destroyed (by dissociative recombination) in the diffuse ISM. Because of the relatively simple networks controlling their abundances, molecular ions are usually good probes of the underlying physical conditions including for instance the fraction of gas in molecular form or the fractional ionization. In this paper we focus on three possible probes of the molecular hydrogen column density, HCO^+^, HOC^+^, and CF^+^. We presented high sensitivity ALMA absorption data toward a sample of compact HII regions and bright QSOs with prominent foreground absorption, in the ground state transitions of the molecular ions HCO^+^, HOC^+^, and CF^+^ and the neutral species HCN and HNC, and from the excited state transitions of C_3_H^+^(4-3) and ^13^CS(2-1). These data are compared with Herschel absorption spectra of the ground state transition of HF and p-H_2_O. We show that the HCO^+^, HOC^+^, and CF^+^ column densities are well correlated with each other. HCO^+^ and HOC^+^ are tightly correlated with p-H_2_O, while they exhibit a different correlation pattern with HF depending on whether the absorbing matter is located in the Galactic disk or in the central molecular zone. We report new detections of C_3_H^+^ confirming that this ion is ubiquitous in the diffuse matter, with an abundance relative to H_2_ of ~7x10^-11^. We confirm that the CF^+^ abundance is lower than predicted by simple chemical models and propose that the rate of the main formation reaction is lower by a factor of about 3 than usually assumed. In the absence of CH or HF data, we recommend to use the ground state transitions of HCO^+^, CCH, and HOC^+^ to trace diffuse molecular hydrogen, with mean abundances relative to H_2_ of 3x10^-9^, 4x10^-8^ and 4x10^-11^ respectively, leading to sensitivity N(H_2_)/{int}{tau}dv of 4x10^20^, 1.5x10^21^, and 6x10^22^cm^-2^/km/s, respectively.
308. M16 SITELLE datacube
ID:
ivo://CDS.VizieR/J/A+A/635/A111
Title:
M16 SITELLE datacube
Short Name:
J/A+A/635/A111
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the very first wide-field, 11' by 11', optical spectral mapping of M16, one of the most famous star-forming regions in the Galaxy. The data were acquired with the new imaging Fourier transform spectrograph SITELLE mounted on the Canada-France-Hawaii Telescope (CFHT). We obtained three spectral cubes with a resolving power of 10000 (SN1 filter), 1500(SN2 filter) and 600 (SN3 filter), centered on the iconic Pillars of Creation and the HH 216 flow, covering the main optical nebular emission lines, namely [OII]{lambda}3726,29 (SN1), H{beta}, [OIII]{lambda}4959,5007 (SN2), [NII]{lambda}6548,84, H{alpha}, and [SII]{lambda}6717,31 (SN3). We validate the performance, calibration, and data reduction of SITELLE, and analyze the structures in the large field-of-view in terms of their kinematics and nebular emission. We compared the SITELLE data to MUSE integral field observations and other spectroscopic and narrow-band imaging data to validate the performance of SITELLE. We computed gas-phase metallicities via the strong-line method, performed a pixel-by-pixel fit to the main emission lines to derive kinematics of the ionized gas, computed the mass-loss rate of the Eastern pillar (also known as the Spire), and combined the SITELLE data with near-infrared narrow-band imaging to characterize the HH 216 flow. The comparison with previously published fluxes demonstrates very good agreement. We disentangle the dependence of the gas-phase metallicities (derived via abundance-tracing line ratios) on the degree of ionization and obtain metallicities that are in excellent agreement with the literature. We confirm the bipolar structure of HH216, find evidence for episodic accretion from the source of the flow, and identify its likely driving source. We compute the mass-loss rate of the Spire pillar on the East side of the HII region and find excellent agreement with the correlation between the mass-loss rate and the ionizing photon flux from the nearby cluster NGC6611.
309. M17-SW datacubes in C and CO lines
ID:
ivo://CDS.VizieR/J/A+A/575/A9
Title:
M17-SW datacubes in C and CO lines
Short Name:
J/A+A/575/A9
Date:
21 Oct 2021
Publisher:
CDS
Description:
We probe the column densities and masses traced by the ionized [CII] and neutral [CI] atomic carbon with spectrally resolved maps, and compare them to the diffuse and dense molecular gas traced by [CI] and low-J CO lines toward the star-forming region M17 SW. We mapped a 4.1pcx4.7pc region in the [CI] 609{mu}m line using the APEX telescope, as well as the CO isotopologues with the IRAM 30m telescope. Data are analyzed based on velocity channel maps that are 1km/s wide. We correlate their spatial distribution with that of the [CII] map obtained with SOFIA/GREAT. Optically thin approximations were used to estimate the column densities of [CI] and [CII] in each velocity channel.
310. MSX 8.3um fluxes of star-forming regions
ID:
ivo://CDS.VizieR/J/AJ/126/1423
Title:
MSX 8.3um fluxes of star-forming regions
Short Name:
J/AJ/126/1423
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have imaged seven nearby star-forming regions, the Rosette Nebula, the Orion Nebula, W3, the Pleiades, G300.2-16.8, S263, and G159.6-18.5, with the Spatial Infrared Imaging Telescope on the Midcourse Space Experiment (MSX) satellite at 18" resolution at 8.3, 12.1, 14.7, and 21.3{mu}m. The large angular scale of the regions imaged (~7.2-50deg^2^) makes these data unique in terms of the combination of size and resolution. In addition to the star-forming regions, two cirrus-free fields (MSXBG 160 and MSXBG 161) and a field near the south Galactic pole (MSXBG 239) were also imaged. Point sources have been extracted from each region, resulting in the identification over 500 new sources (i.e., no identified counterparts at other wavelengths), as well as over 1300 with prior identifications. The extended emission from the star-forming regions is described, and prominent structures are identified, particularly in W3 and Orion. The Rosette Nebula is discussed in detail. The bulk of the mid-infrared emission is consistent with that of photon-dominated regions, including the elephant trunk complex. The central clump, however, and a line of site toward the northern edge of the cavity show significantly redder colors than the rest of the Rosette complex.

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