- ID:
- ivo://CDS.VizieR/J/A+A/626/A131
- Title:
- G287.84-0.82 SOFIA and APEX datacubes
- Short Name:
- J/A+A/626/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have mapped the G287.84-0.82 cometary globule (with the Treasure Chest cluster embedded in it) in the South Pillars region of Carina (i) in [CII], 63um [OI] , and CO(11-10) using the heterodyne receiver array upGREAT on SOFIA and (ii) in J=2-1 transitions of CO, ^13^CO, C^18^O and J=3-2 transitions of H_2_CO using the APEX telescope in Chile. We use these data to probe the morphology, kinematics, and physical conditions of the molecular gas and the photon dominated regions (PDRs) in G287.84-0.82. The velocity-resolved observations of [CII] and [OI] suggest that the overall structure of the pillar (with red-shifted photo evaporating tails) is consistent with the effect of FUV radiation and winds from eta-Car and O stars in Trumpler 16. The gas in the head of the pillar is strongly influenced by the embedded cluster, whose brightest member is an O9.5 V star, CPD -59 2661. The emission of the [CII] and [OI] lines peak at a position close to the embedded star, while all the other tracers peak at another position lying to the north-east consistent with gas being compressed by the expanding PDR created by the embedded cluster. The molecular gas inside the globule is probed with the J=2-1 transitions of CO and isotopologues as well as H_2_CO, and analyzed using a non-LTE model (escape-probability approach), while we use PDR models to derive the physical conditions of the PDR. We identify at least two PDR gas components; the diffuse part (~10^4cm^-3^) is traced by [CII], while the dense (n~2-8x10^5^cm^-3^) part is traced by [CII], [OI], CO(11-10). Using the the F=2-1 transition of [^13^CII] detected at 50 positions in the region, we derive optical depths (0.9-5), excitation temperatures of [CII] (80-255K), and N(C+) of 0.3-1x10^19^cm^-2^. The total mass of the globule is ~1000M_{sun}_, about half of which is traced by [CII]. The dense PDR gas has a thermal pressure of 10^7-10^8K/cm^3^, which is similar to the values observed in other regions.
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5772. G328.2551-0.5321 spectra
- ID:
- ivo://CDS.VizieR/J/A+A/632/A57
- Title:
- G328.2551-0.5321 spectra
- Short Name:
- J/A+A/632/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical hot cores are rich in molecular emission, and they show a high abundance of complex organic molecules (COMs). The emergence of molecular complexity that is represented by COMs, in particular, is poorly constrained in the early evolution of hot cores. We put observational constraints on the physical location of COMs in a resolved high-mass protostellar envelope associated with the G328.2551-0.5321 clump. The protostar is single down to 400au scales and we resolved the envelope structure down to this scale. High angular resolution observations using the Atacama Large Millimeter Array allowed us to resolve the structure of the inner envelope and pin down the emission region of COMs. We use local thermodynamic equilibrium modelling of the available 7.5GHz bandwidth around 345GHz to identify the COMs towards two accretion shocks and a selected position representing the bulk emission of the inner envelope. We quantitatively discuss the derived molecular column densities and abundances towards these positions, and use our line identification to qualitatively compare this to the emission of COMs seen towards the central position, corresponding to the protostar and its accretion disk. We detect emission from 10 COMs, and identify a line of deuterated water (HDO). In addition to methanol (CH_3_OH), methyl formate (CH_3_OCHO) and formamide (HC(O)NH_2_) have the most extended emission. Together with HDO, these molecules are found to be associated with both the accretion shocks and the inner envelope, which has a moderate temperature of Tkin~110K. We find a significant difference in the distribution of COMs. O-bearing COMs, such as ethanol, acetone, and ethylene glycol are almost exclusively found and show a higher abundance towards the accretion shocks with Tkin~180K. Whereas N-bearing COMs with a CN group, such as vinyl and ethyl cyanide peak on the central position, thus the protostar and the accretion disk. The molecular composition is similar towards the two shock positions, while it is significantly different towards the inner envelope, suggesting an increase in abundance of O-bearing COMs towards the accretion shocks. We present the first observational evidence for a large column density of COMs seen towards accretion shocks at the centrifugal barrier at the inner envelope. The overall molecular emission shows increased molecular abundances of COMs towards the accretion shocks compared to the inner envelope. The bulk of the gas from the inner envelope is still at a moderate temperature of Tkin~110K, and we find that the radiatively heated inner region is very compact (<1000au). Since the molecular composition is dominated by that of the accretion shocks and the radiatively heated hot inner region is very compact, we propose this source to be a precursor to a classical, radiatively heated hot core. By imaging the physical location of HDO, we find that it is consistent with an origin within the moderately heated inner envelope, suggesting that it originates from sublimation of ice from the grain surface and its destruction in the vicinity of the heating source has not been efficient yet.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/2003
- Title:
- G305 star-forming complex in ^13^CO
- Short Name:
- J/MNRAS/435/2003
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 109-115GHz (3mm) wide-field spectral line observations of ^12^CO, ^13^CO and C^18^O J=1-0 molecular emission and 5.5 and 8.8GHz (6 and 3cm) radio continuum emission towards the high-mass star-forming complex known as G305. The morphology of G305 is dominated by a large evacuated cavity at the centre of the complex driven by clusters of O stars surrounded by molecular gas. Our goals are to determine the physical properties of the molecular environment and reveal the relationship between the molecular and ionized gas and star formation in G305. This is in an effort to characterize the star-forming environment and constrain the star formation history in an attempt to evaluate the impact of high-mass stars on the evolution of the G305 complex. Analysis of CO emission in G305 reveals 156 molecular clumps with the following physical characteristics; excitation temperatures ranging from 7 to 25K, optical depths of 0.2-0.9, H_2_) column densities of 0.1-4.0x10^22^cm^-2^, clump masses ranging from 10^2^ to 10^4^M_{sun}_ and a total molecular mass of >3.5x10^5^M_{sun}_. The 5.5 and 8.8GHz radio continuum emission reveals an extended low surface brightness ionized environment within which we identify 15 large-scale features with a further eight smaller sources projected within these features. By comparing to mid-infrared emission and archival data, we identify nine HII regions, seven compact HII regions, one UC HII region and four extended regions. The total integrated flux of the radio continuum emission at 5.5GHz is ~ 180Jy corresponding to a Lyman continuum output of 2.4x10^50^photons/s. We compare the ionized and molecular environment with optically identified high-mass stars and ongoing star formation, identified from the literature. Analysis of this data set reveals a star formation rate of 0.008-0.016M_{sun}_/yr and efficiency of 7-12%, allows us to probe the star formation history of the region and discuss the impact of high-mass stars on the evolution of G305.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A54
- Title:
- G31.41+0.31 Stokes IQU images
- Short Name:
- J/A+A/630/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Submillimeter Array (SMA) 870um polarization observations of the hot molecular core G31.41+0.31 revealed one of the clearest examples up to date of an hourglass-shaped magnetic field morphology in a high-mass star-forming region. To better establish the role that the magnetic field plays in the collapse of G31.41+0.31, we carried out Atacama Large Millimeter/submillimeter Array (ALMA) observations of the polarized dust continuum emission at 1.3mm with an angular resolution four times higher than that of the previous (sub)millimeter observations to achieve an unprecedented image of the magnetic field morphology. We used ALMA to perform full polarization observations at 233GHz (Band 6). The resulting synthesized beam is 00.28"x00.20" which, at the distance of the source, corresponds to a spatial resolution of 875au. The observations resolve the structure of the magnetic field in G31.41+0.31 and allow us to study the field in detail. The polarized emission in the Main core of G31.41+0.41 is successfully fit with a semi-analytical magnetostatic model of a toroid supported by magnetic fields. The best fit model suggests that the magnetic field is well represented by a poloidal field with a possible contribution of a toroidal component of 10% of the poloidal component, oriented southeast to northwest at ~-44{deg} and with an inclination of ~-45{deg}. The magnetic field is oriented perpendicular to the northeast to southwest velocity gradient detected in this core on scales from 10^3^-10^4^au. This supports the hypothesis that the velocity gradient is due to rotation of the core and suggests that such a rotation has little effect on the magnetic field. The strength of the magnetic field estimated in the central region of the core with the Davis-Chandrasekhar-Fermi method is ~8-13mG and implies that the mass-to-flux ratio in this region is slightly supercritical ({lambda}=1.4-2.2). The magnetic field in G31.41+0.31 maintains an hourglass-shaped morphology down to scales of <1000au. Despite the magnetic field being important in G31.41+0.31, it is not enough to prevent fragmentation and collapse of the core, as demonstrated by the presence of at least four sources embedded in the center of the core.
- ID:
- ivo://svo.cab/cat/gtc-osiris-detection
- Title:
- GTC OSIRIS Broad Band DR1: detection catalogue
- Short Name:
- OSIRIS detection
- Date:
- 03 Jun 2020 15:30:08
- Publisher:
- SVO/CAB
- Description:
- GTC OSIRIS Broad Band First Data Release: detection catalogue
- ID:
- ivo://svo.cab/cat/gtc-osiris-source
- Title:
- GTC OSIRIS Broad Band DR1: source catalogue
- Short Name:
- OSIRIS source
- Date:
- 03 Jun 2020 15:30:17
- Publisher:
- SVO/CAB
- Description:
- GTC OSIRIS Broad Band First Data Release: source catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/570/A96
- Title:
- GTC spectra of z~2.3 quasars
- Short Name:
- J/A+A/570/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The advent of 8-10m class telescopes for the first time makes it possible to compare in detail quasars with similar luminosity and very different redshifts. We conducted a search for z-dependent gradients in line-emission diagnostics and derived physical properties by comparing, in a narrow bolometric luminosity range (logL~46.1+/-0.4erg/s), some of the most luminous local z<0.6 quasars with some of the lowest luminosity sources yet found at redshift z=2.1-2.5. Moderate signal-to-noise ratio spectra for 22 high-redshift sources were obtained with the 10.4m Gran Telescopio Canarias (GTC), for which the HST (largely the Faint Object Spectrograph) archive provides a low-redshift control sample. We compared the spectra in the context of the 4D Eigenvector 1 formalism, meaning that we divided both source samples into highly accreting population A and population B sources accreting at a lower rate. CIV {lambda}1549, the strongest and most reliable diagnostic line, shows very similar properties at both redshifts, which confirms the CIV {lambda}1549 profile differences at high redshift between populations A and B, which are well established in local quasars. The CIV {lambda}1549 blueshift that appears quasi-ubiquitous in higher L sources is found in only half (population A) of the quasars observed in the two samples. A CIV {lambda}1549 evolutionary Baldwin effect is certainly disfavored. We find evidence for lower metallicity in the GTC sample that may point toward a gradient with z. No evidence for a gradient in black hole mass or Eddington ratio is found. Spectroscopic differences established at low z are also present in much higher redshift quasars. Our results on the CIV {lambda}1549 blueshift suggest that it depends both on source luminosity and Eddington ratio. Given that our samples involve sources with very similar luminosity, the evidence for a systematic metallicity decrease, if real, points toward an evolutionary effect. Our samples are not large enough to effectively constrain possible changes of black hole mass or Eddington ratio with redshift. The two samples appear representative of a slowly evolving quasar population that is most likely present at all redshifts.
- ID:
- ivo://archive.stsci.edu/gsc/gsc2.3
- Title:
- Guide Star Catalog 2.3 Cone Search
- Short Name:
- GSC23
- Date:
- 13 Feb 2020 17:10:38
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The Guide Star Catalog II (GSC-II) is an all-sky optical catalog based on 1" resolution scans of the photographic Sky Survey plates, at two epochs and three bandpasses, from the Palomar and UK Schmidt telescopes. This all-sky catalog will ultimately contains positions, proper motions, classifications, and magnitudes in multiple bandpasses for almost a billion objects down to approximately Jpg=21, Fpg=20. The GSC-II is currently used for HST Bright Object Protection and HST pointing. Looking ahead, the GSC-II will form the basis of the Guide Star Catalog for JWST. This was constructed in collaboration with ground-based observatories for use with the GEMINI, VLT and GALILEO telescopes
- ID:
- ivo://archive.stsci.edu/gsc/gsc1.1
- Title:
- Guide Star Catalog 1.1 Cone Search
- Short Name:
- GSC11
- Date:
- 13 Feb 2020 17:10:22
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The GSC-I catalog is an all-sky catalog of positions and magnitudes for approximately 19 million stars and other objects in the sixth to fifteenth magnitude range. The GSC is primarily based on an all-sky, single-epoch collection of Schmidt plates. For centers at +6 degrees and north, a 1982 epoch "Quick V" survey was obtained from the Palomar Observatory, while for southern fields, materials from the UK SERC J survey (epoch = 1975) and its equatorial extension (epoch = 1982) were used.
- ID:
- ivo://CDS.VizieR/II/143A
- Title:
- Guide Star Photometric Catalog, Updated Version 1
- Short Name:
- II/143A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Guide Star Photometric Catalog (GSPC) is an all-sky set of 1477 photoelectrically determined BV sequences covering the magnitude range from 9 to 15. The GSPC was created to provide photometric calibrators for the HST Guide Star Catalog (GSC). Each sequence nominally contains (at least) six stars, each with a photometric precision of 0.05 mag. In practice, a small number of sequences contain fewer stars; and the precisions achieved for the faintest stars are more nearly 0.1 mag. For declinations greater than +3 degrees the sequences generally lie near the centers of the original Palomar Observatory - National Geographic Society Sky Atlas. Other sequences lie near the centers of the ESO/SERC Southern Sky Atlas. The catalog also includes a list of suspected variable stars, a bibliography of literature sequences, and additional information which was useful in the data reduction and for quality control of the final catalog. The full catalog is made of 7 FITS files: tables 1 to 5, references (table 6 of the paper) and the actual catalogue (table 7 of the paper). The ascii versions of Tables 1 to 5 are included in this file; the ascii version of the references (refs.dat) and of the actual catalogue (catalog.dat) are described here. The updated version 1 was created by replacing photometric sequences P040, P421, S335 and S742 in GSPC version 1. The updated sequences have improved photometry and/or positions. In addition the sigma's in V and B-V (here e_V and e_B-V) were replaced with the values provided by the authors when we noted a discrepancy with the published values.