- ID:
- ivo://CDS.VizieR/J/A+A/538/A11
- Title:
- 70um-1.2mm and N_2_H+ maps of IRDC18454 (W43)
- Short Name:
- J/A+A/538/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The earliest stages of high-mass star formation are still poorly characterized. Densities, temperatures and kinematics are crucial parameters for simulations of high-mass star formation. It is also unknown whether the initial conditions vary with environment. We want to investigate the youngest massive gas clumps in the environment of extremely active star formation. We selected the IRDC18454 complex, directly associated with the W43 Galactic mini-starburst, and observed it in the continuum emission between 70um and 1.2mm with Herschel, APEX and the 30m telescope, and in spectral line emission of N_2_H+ and ^13^CO with the Nobeyama 45m, the IRAM 30m and the Plateau de Bure Interferometer.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/663
- Title:
- 850um observations of W3 giant molecular cloud
- Short Name:
- J/MNRAS/379/663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have surveyed a ~0.9 square degree area of the W3 giant molecular cloud (GMC) and star-forming region in the 850-um continuum, using the Submillimetre Common-User Bolometer Array on the James Clerk Maxwell Telescope. A complete sample of 316 dense clumps were detected with a mass range from around 13 to 2500M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJS/186/406
- Title:
- 350um polarimetry from CSO
- Short Name:
- J/ApJS/186/406
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a summary of data obtained with the 350um polarimeter, Hertz, at the Caltech Submillimeter Observatory. We give tabulated results and maps showing polarization vectors and intensity contours. The summary includes over 4300 individual measurements in 56 Galactic sources and two galaxies. Of these measurements, 2153 have P>=3{sigma}_p_ statistical significance. The median polarization of the entire data set is 1.46%.
- ID:
- ivo://CDS.VizieR/J/ApJS/249/1
- Title:
- 500um risers with HerMES & SPIRE drop-outs with S2CLS
- Short Name:
- J/ApJS/249/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our systematic search for the reddest far-infrared (FIR) and submillimeter (sub-mm) galaxies using the data from the Herschel Multi-tiered Extragalactic Survey (HerMES) and the SCUBA2 Cosmological Legacy Survey (S2CLS). The red FIR galaxies are "500{mu}m risers," whose spectral energy distributions increase with wavelength across the three FIR passbands of the Spectral and Photometric Imaging REceiver (SPIRE) of Herschel. Within 106.5deg^2^ of the HerMES fields, we have selected 629 500{mu}m risers. The red sub-mm galaxies are "SPIRE drop-outs," which are prominent detections in the S2CLS 850{mu}m data but are extremely weak or invisible in the SPIRE bands. Within the 2.98deg^2^ common area of HerMES and S2CLS, we have selected 95 such objects. These very red sources could be dusty starbursts at high redshifts (z>~4-6) because the peak of their cold-dust emission heated by star formation is shifted to the reddest FIR/sub-mm bands. The surface density of 500{mu}m risers is ~8.2deg^-2^ at the >=20mJy level in 500{mu}m, while that of SPIRE drop-outs is ~19.3deg^-2^ at the >=5mJy level in 850{mu}m. Both types of objects could span a wide range of redshifts, however. Using deep radio data in these fields to further select the ones likely at the highest redshifts, we find that the surface density of z>6 candidates is 5.5deg^-2^ among 500{mu}m risers and is 0.8-13.6deg^-2^ among SPIRE drop-outs. If this is correct, the dust-embedded star formation processes in such objects could contribute comparably as Lyman-break galaxies to the global SFR density at z>6.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A14
- Title:
- Updated Planck catalogue PSZ1
- Short Name:
- J/A+A/581/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We update the all-sky Planck catalogue of 1227 clusters and cluster candidates (PSZ1) published in March 2013, derived from detections of the Sunyaev-Zeldovich (SZ) effect using the first 15.5 months of Planck satellite observations. As an addendum, we deliver an updated version of the PSZ1 catalogue, reporting the further confirmation of 86 Planck-discovered clusters. In total, the PSZ1 now contains 947 confirmed clusters, of which 214 were confirmed as newly discovered clusters through follow-up observations undertaken by the Planck Collaboration. The updated PSZ1 contains redshifts for 913 systems, of which 736 (~80.6%) are spectroscopic, and associated mass estimates derived from the Yz mass proxy. We also provide a new SZ quality flag for the remaining 280 candidates. This flag was derived from a novel artificial neural-network classification of the SZ signal. Based on this assessment, the purity of the updated PSZ1 catalogue is estimated to be 94%. In this release, we provide the full updated catalogue and an additional readme file with further information on the Planck SZ detections.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/130
- Title:
- VANDAM survey of Orion protostars. II.
- Short Name:
- J/ApJ/890/130
- Date:
- 07 Mar 2022 13:26:15
- Publisher:
- CDS
- Description:
- We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87mm at a resolution of ~0.1" (40au), including observations with the Very Large Array at 9mm toward 148 protostars at a resolution of ~0.08" (32au). This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are 44.9_-3.4_^+5.8^, 37.0_-3.0_^+4.9^, and 28.5_-2.3_^+3.7^au, respectively, and the mean protostellar dust disk masses are 25.9_-4.0_^+7.7^, 14.9_-2.2_^+3.8^, 11.6_-1.9_^+3.5^M_{Earth}_, respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87mm continuum sources plus 42 nondetections) have disk radii greater than 50au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/26
- Title:
- Very Low-Luminosity Objects (VeLLOs) from 1.25-850um
- Short Name:
- J/ApJS/225/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for Very Low-Luminosity Objects (VeLLOs) in the Gould Belt (GB) clouds using infrared and sub-millimeter (sub-mm) data from 1.25 to 850{mu}m and our N_2_H^+^(J=1-0) observations. We modified the criteria by Dunham et al. (2008, J/ApJS/179/249) to select the VeLLOs in the GB clouds, finding 95 VeLLO candidates, 79 of which are newly identified in this study. Out of 95 sources, 44 were detected in both sub-mm continuum and N_2_H^+^ emission and were classified as Group A (the VeLLOs), and 51 sources detected in either sub-mm emission or N_2_H^+^ emission were classified with Group B as candidate VeLLOs. We find that these VeLLOs and the candidates are forming in environments different from those of the likely VeLLOs. Seventy-eight sources are embedded within their molecular clouds, and thus are likely VeLLOs forming in a dense environment. The remaining 17 sources are located in low-level extinction regions (A_V_<1) connected to the clouds, and can be either background sources or candidate substellar objects forming in an isolated mode. The VeLLOs and the candidates are likely more luminous and their envelopes tend to be more massive in denser environments. The VeLLOs and the candidates are more populous in the clouds where more YSOs form, indicating that they form in a manner similar to that of normal YSOs. The bolometric luminosities and temperatures of the VeLLOs are compared to predictions of episodic accretion models, showing that the low luminosities for most VeLLOs can be well explained by their status in the quiescent phases of a cycle of episodic mass accretion.
- ID:
- ivo://CDS.VizieR/J/ApJ/846/144
- Title:
- Virial analysis of the dense cores in Orion A
- Short Name:
- J/ApJ/846/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use data on gas temperature and velocity dispersion from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. Surprisingly, we find that almost none of the dense cores are sufficiently massive to be bound when considering only the balance between self-gravity and the thermal and non-thermal motions present in the dense gas. Including the additional pressure binding imposed by the weight of the ambient molecular cloud material and additional smaller pressure terms, however, suggests that most of the dense cores are pressure-confined.
- ID:
- ivo://CDS.VizieR/J/ApJ/802/69
- Title:
- VLA, ALMA and SMA monitoring of Sgr A*
- Short Name:
- J/ApJ/802/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report new observations with the Very Large Array, Atacama Large Millimeter Array, and Submillimeter Array at frequencies from 1.0 to 355GHz of the Galactic Center black hole, Sagittarius A*. These observations were conducted between 2012 October and 2014 November. While we see variability over the whole spectrum with an amplitude as large as a factor of 2 at millimeter wavelengths, we find no evidence for a change in the mean flux density or spectrum of Sgr A* that can be attributed to interaction with the G2 source. The absence of a bow shock at low frequencies is consistent with a cross-sectional area for G2 that is less than 2x10^29^cm2. This result fits with several model predictions including a magnetically arrested cloud, a pressure-confined stellar wind, and a stellar photosphere of a binary merger. There is no evidence for enhanced accretion onto the black hole driving greater jet and/or accretion flow emission. Finally, we measure the millimeter wavelength spectral index of Sgr A* to be flat; combined with previous measurements, this suggests that there is no spectral break between 230 and 690GHz. The emission region is thus likely in a transition between optically thick and thin at these frequencies and requires a mix of lepton distributions with varying temperatures consistent with stratification.
- ID:
- ivo://CDS.VizieR/J/ApJ/707/283
- Title:
- VLA observation of molecular clumps
- Short Name:
- J/ApJ/707/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a search for ionized gas at 3.6cm, using the Very Large Array, toward 31 Galactic intermediate- and high-mass clumps detected in previous millimeter continuum observations. In the 10 observed fields, 35 HII regions are identified, of which 20 are newly discovered. Many of the HII regions are multiply peaked indicating the presence of a cluster of massive stars. We find that the ionized gas tends to be associated toward the millimeter clumps; of the 31 millimeter clumps observed, nine of these appear to be physically related to ionized gas, and a further six have ionized gas emission within 1'. For clumps with associated ionized gas, the combined mass of the ionizing massive stars is compared to the clump masses to provide an estimate of the instantaneous star formation efficiency. These values range from a few percent to 25%, and have an average of 7%+/-8%. We also find a correlation between the clump mass and the mass of the ionizing massive stars within it, which is consistent with a power law. This result is comparable to the prediction of star formation by competitive accretion that a power-law relationship exists between the mass of the most massive star in a cluster and the total mass of the remaining stars.
