- ID:
- ivo://CDS.VizieR/J/A+A/594/A28
- Title:
- Planck Catalogue of Galactic cold clumps (PGCC)
- Short Name:
- J/A+A/594/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Planck Catalogue of Galactic Cold Clumps (PGCC), an all-sky catalogue of Galactic cold clump candidates detected by Planck. This catalogue is the full version of the Early Cold Core (ECC) catalogue, which was made available in 2011 with the Early Release Compact Source Catalogue (ERCSC) and which contained 915 high signal-to-noise sources. It is based on the Planck 48-month mission data that are currently being released to the astronomical community. The PGCC catalogue is an observational catalogue consisting exclusively of Galactic cold sources. The three highest Planck bands (857, 454, and 353GHz) have been combined with IRAS data at 3THz to perform a multi-frequency detection of sources colder than their local environment. After rejection of possible extragalactic contaminants, the PGCC catalogue contains 13188 Galactic sources spread across the whole sky, i.e., from the Galactic plane to high latitudes, following the spatial distribution of the main molecular cloud complexes. The median temperature of PGCC sources lies between 13 and 14.5K, depending on the quality of the flux density measurements, with a temperature ranging from 5.8 to 20K after removing the sources with the top 1% highest temperature estimates. Using seven independent methods, reliable distance estimates have been obtained for 5574 sources, which allows us to derive their physical properties such as their mass, physical size, mean density, and luminosity. The PGCC sources are located mainly in the solar neighbourhood, but also up to a distance of 10.5kpc in the direction of the Galactic centre, and range from low-mass cores to large molecular clouds. Because of this diversity and because the PGCC catalogue contains sources in very different environments, the catalogue is useful for investigating the evolution from molecular clouds to cores. Finally, it also includes 54 additional sources located in the Small and Large Magellanic Clouds.
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- ID:
- ivo://CDS.VizieR/J/ApJ/864/154
- Title:
- Planck cold clump G108.37-01.06 YSO candidates
- Short Name:
- J/ApJ/864/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck Galactic Cold Clumps (PGCCs) are possible representations of the initial conditions and very early stages of star formation. With the objective of understanding better the star and star cluster formation, we probe the molecular cloud associated with PGCC G108.37-01.06 (hereafter PG108.3), which can be traced in a velocity range of -57 to -51km/s. The INT Photometric H{alpha} Survey images reveal H{alpha} emission at various locations around PG108.3, and optical spectroscopy of the bright sources in those zones of H{alpha} emission discloses two massive ionizing sources with spectral type O8-O9V and B1V. Using the radio continuum, we estimate ionizing gas parameters and find the dynamical ages of HII regions associated with the massive stars in the range of 0.5-0.75Myr. Based on the stellar surface density map constructed from the deep near-infrared Canada-France-Hawaii Telescope observations, we find two prominent star clusters in PG108.3; of these, the cluster associated with H ii region S148 is moderately massive (~240M_{sun}_). A careful inspection of James Clerk Maxwell telescope ^13^CO (3-2) molecular data exhibits that the massive cluster is associated with a number of filamentary structures. Several embedded young stellar objects (YSOs) are also identified in PG108.3 along the length and junction of filaments. We find evidence of a velocity gradient along the length of the filaments. Along with kinematics of the filaments and the distribution of ionized, molecular gas and YSOs, we suggest that the cluster formation is most likely due to the longitudinal collapse of the most massive filament in PG108.3.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/43
- Title:
- Planck cold clumps and cores in the 2nd quadrant
- Short Name:
- J/ApJS/224/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ninety-six Planck cold dust clumps in the second quadrant were mapped with ^12^CO(1-0), ^13^CO(1-0), and C^18^O(1-0) lines at the 13.7m telescope of Purple Mountain Observatory. ^12^CO(1-0) and ^13^CO(1-0) emissions were detected for all 96 clumps, while C^18^O(1-0) emissions were detected in 81 of them. Fifteen clumps have more than one velocity component. In the 115 mapped velocity components, 225 cores were obtained. We found that 23.1% of the cores have non-Gaussian profiles. We acquired the V_lsr_, FWHM, and T_A_ of the lines. Distances, T_ex_, velocity dispersions, N_H_2__, and masses were also derived. Generally, turbulence may dominant the cores because {sigma}_NT_/{sigma}_Therm_>1 in almost all of the cores and Larson's relationship is not apparent in our massive cores. Virial parameters are adopted to test the gravitational stability of cores and 51% of the cores are likely collapsing. The core mass function of the cores in the range 0-1kpc suggests a low core-to-star conversional efficiency (0.62%). Only 14 of 225 cores (6.2%) have associated stellar objects at their centers, while the others are starless. The morphologies of clumps are mainly filamentary structures. Seven clumps may be located on an extension of the new spiral arm in the second quadrant while three are on the known outer arm.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/37
- Title:
- Planck cold clumps in ^12^CO, ^13^CO and C^18^O
- Short Name:
- J/ApJS/209/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A mapping study of 71 Planck cold clumps was made with ^12^CO(1-0), ^13^CO(1-0), and C^18^O(1-0) lines at the 13.7m telescope of Purple Mountain Observatory. For all the clumps, ^12^CO(1-0) and ^13^CO(1-0) emissions were detected, while for 55 of them, C^18^O(1-0) emissions were detected. Of the 71 Clumps, 34 are in the Taurus Complex, 24 in the California Complex, and 13 are in the Perseus Complex. In the 76 velocity components, 38 cores are found in 27 clumps; 19 of these cores are in the Taurus Complex, 16 in the California Complex, and 3 in the Perseus Complex. We acquired V_lsr_, T_A_ and FWHM of lines. Physical parameters including T_ex_, N_H2_, {sigma}_Therm_, {sigma}_NT_, and {sigma}_3D_were calculated. Generally, the cores are of T_ex_=2-16K, N_H2_/cm2, and {sigma}_3D_=0.2-1.0km/s. In the Taurus Complex, the cores are less dense on average and have smaller {sigma}_Therm_than the cores in the Perseus and California Complexes. Two of the three cores in the Perseus Complex are revealed to have larger T_ex_, N_H2_, and {sigma}_3D_ than the mean values in the other two regions. Most of the cores have {sigma}_NT_larger than {sigma}_Therm_, suggesting a dominance of turbulence in our cores. The majority of the cores have M_vir_/M_LTE_{Gt} 1, which indicates these cores are not bound and will disperse. By comparing our results with the dust properties revealed by the Planck Early Release Cold Cores Catalog, we investigated the coupling of gas and dust components. We found that most of the cores have dust temperatures higher than their gas temperatures. The stellar objects associated with our sources were checked and 90% of the cores were found to be starless.
- ID:
- ivo://CDS.VizieR/J/ApJS/254/14
- Title:
- Planck Cold Clumps in the lambda Orionis complex. III.
- Short Name:
- J/ApJS/254/14
- Date:
- 17 Jan 2022 00:15:36
- Publisher:
- CDS
- Description:
- Massive stars have a strong impact on their local environments. However, how stellar feedback regulates star formation is still under debate. In this context, we studied the chemical properties of 80 dense cores in the Orion molecular cloud complex composed of the Orion A (39 cores), B (26 cores), and {lambda} Orionis (15 cores) clouds using multiple molecular line data taken with the Korean Very Long Baseline Interferometry Network 21m telescopes. The {lambda} Orionis cloud has an HII bubble surrounding the O-type star {lambda} Ori, and hence it is exposed to the ultraviolet (UV) radiation field of the massive star. The abundances of C_2_H and HCN, which are sensitive to UV radiation, appear to be higher in the cores in the {lambda} Orionis cloud than in those in the Orion A and B clouds, while the HDCO to H_2_CO abundance ratios show the opposite trend, indicating warmer conditions in the {lambda} Orionis cloud. The detection rates of dense gas tracers such as the N_2_H^+^, HCO^+^, and H^13^CO^+^ lines are also lower in the {lambda} Orionis cloud. These chemical properties imply that the cores in the {lambda} Orionis cloud are heated by UV photons from {lambda} Ori. Furthermore, the cores in the {lambda} Orionis cloud do not show any statistically significant excess in the infall signature of HCO^+^ (1-0), unlike those in the Orion A and B clouds. Our results support the idea that feedback from massive stars impacts star formation in a negative way by heating and evaporating dense materials, as in the {lambda} Orionis cloud.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/4
- Title:
- Planck cold clumps survey in the Orion complex
- Short Name:
- J/ApJS/202/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A mapping survey of 51 Planck cold clumps projected on the Orion complex was performed with J=1-0 lines of ^12^CO and ^13^CO with the 13.7m telescope at the Purple Mountain Observatory. The mean column densities of the Planck gas clumps range from 0.5 to 9.5x10^21^cm^-2^, with an average value of (2.9+/-1.9)x10^21^cm^-2^. The mean excitation temperatures of these clumps range from 7.4 to 21.1K, with an average value of 12.1+/-3.0K and the average three-dimensional velocity dispersion {sigma}_3D_ in these molecular clumps is 0.66+/-0.24km/s. The H2 column density of the molecular clumps calculated from molecular lines correlates with the aperture flux at 857GHz of the dust emission. By analyzing the distributions of the physical parameters, we suggest that turbulent flows can shape the clump structure and dominate their density distribution on large scales, but not function on small scales due to local fluctuations. Eighty-two dense cores are identified in the molecular clumps. The dense cores have an average radius and local thermal equilibrium (LTE) mass of 0.34+/-0.14pc and 38^+5^_-30_M_{sun}_, respectively. The structures of low column density cores are more affected by turbulence, while the structures of high column density cores are more affected by other factors, especially by gravity.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/76
- Title:
- Planck cold dust clumps CO survey
- Short Name:
- J/ApJ/756/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey toward 674 Planck cold clumps of the Early Cold Core Catalogue (ECC) in the J=1-0 transitions of ^12^CO, ^13^CO, and C^18^O has been carried out using the Purple Mountain Observatory 13.7m telescope. Six hundred seventy-three clumps were detected with ^12^CO and ^13^CO emission, and 68% of the sample has C^18^O emission. Additional velocity components were also identified. A close consistency of the three line peak velocities was revealed for the first time. Kinematic distances are given for all the velocity components, and half of the clumps are located within 0.5 and 1.5kpc. Excitation temperatures range from 4 to 27K, slightly larger than those of T_d_. Line width analysis shows that the majority of ECC clumps are low-mass clumps. Ten clumps were mapped. Twelve velocity components and 22 cores were obtained. Their morphologies include extended diffuse, dense, isolated, cometary, and filament, of which the last is the majority. Twenty cores are starless, and only seven cores seem to be in a gravitationally bound state. Planck cold clumps are the most quiescent among the samples of weak red IRAS, infrared dark clouds, UC HII candidates, extended green objects, and methanol maser sources, suggesting that Planck cold clumps have expanded the horizon of cold astronomy.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A103
- Title:
- Planetary nebulae monochromatic images atlas
- Short Name:
- J/A+A/592/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an atlas of more than one hundred original images of planetary nebulae (PNe). These images were taken in a narrow-band filter centred on the nebular emission of the [NII] during several observing campaigns using two moderate-aperture telescopes, at the Complejo Astronomico El Leoncito (CASLEO), and the Estacion Astrofisica de Bosque Alegre (EABA), both in Argentina. The data provided by this atlas represent one of the most extensive image surveys of PNe in [NII]. We compare the new images with those available in the literature, and briefly describe all cases in which our [NII] images reveal new and interesting structures.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A93
- Title:
- Polar dust obscuration in broad-line AGN
- Short Name:
- J/A+A/654/A93
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We study a sample of 1275 broad-line AGN in the XMM-XXL field, with optical to infrared photometric data. These AGN are seen along their polar direction and we expect a maximal impact of dust located around the poles when it is present. We use X-CIGALE, which introduces a dust component to account for obscuration along the polar directions, modeled as a foreground screen, and an extinction curve that is chosen as it steepens significantly at short wavelengths or is much grayer. By comparing the results of different fits, we are able to define subsamples of sources with positive statistical evidence in favor of or against polar obscuration (if present) and described using the gray or steep extinction curve. We find a similar fraction of sources with positive evidence for and against polar dust. Applying statistical corrections, we estimate that half of our sample could contain polar dust and among them, 60% exhibit a steep extinction curve and 40% a flat extinction curve; although these latter percentages are found to depend on the adopted extinction curves. The obscuration in the V-band is not found to correlate with the X-ray column density, while A_V_/N_H_ ratios span a large range of values and higher dust temperatures are found with the flat, rather than with the steep extinction curve. Ignoring this polar dust component in the fit of the spectral energy distribution of these composite systems leads to an overestimation of the stellar contribution. A single fit with a polar dust component described with an SMC extinction curve efficiently overcomes this issue but it fails at identifying all the AGN with polar dust obscuration.
- ID:
- ivo://CDS.VizieR/J/ApJ/849/157
- Title:
- Polarimetry obs. toward IC5146 background stars
- Short Name:
- J/ApJ/849/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared stellar polarization observations toward the dark filamentary clouds associated with IC5146. The data allow us to investigate the dust properties (this paper) and the magnetic field structure (Paper II). A total of 2022 background stars were detected in the Rc, i', H, and/or K bands to A_V_<~25mag. The ratio of the polarization percentage at different wavelengths provides an estimate of {lambda}_max_, the wavelength of the peak polarization, which is an indicator of the small-size cutoff of the grain size distribution. The grain size distribution seems to significantly change at A_V_~3mag, where both the average and dispersion of P_Rc_/P_H_ decrease. In addition, we found {lambda}_max_~0.6-0.9{mu}m for A_V_>2.5mag, which is larger than the ~0.55{mu}m in the general interstellar medium (ISM), suggesting that grain growth has already started in low-AV regions. Our data also reveal that polarization efficiency (PE=P_{lambda}_/A_V_) decreases with A_V_ as a power law in the Rc, i', and K bands with indices of -0.71+/-0.10, -1.23+/-0.10, and -0.53+/-0.09. However, H-band data show a power index change; the PE varies with A_V_ steeply (index of -0.95+/-0.30) when A_V_<2.88+/-0.67mag, but softly (index of -0.25+/-0.06) for greater AV values. The soft decay of PE in high-AV regions is consistent with the radiative alignment torque model, suggesting that our data trace the magnetic field to A_V_~20mag. Furthermore, the breakpoint found in the H band is similar to that for A_V_, where we found the P_Rc_/P_H_ dispersion significantly decreased. Therefore, the flat PE-A_V_ in high-A_V_ regions implies that the power-index changes result from additional grain growth.
