- ID:
- ivo://CDS.VizieR/J/A+A/641/A54
- Title:
- Complex organic molecules in high-mass SFRs
- Short Name:
- J/A+A/641/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have studied four complex organic molecules (COMs), the oxygen-bearing methyl formate (CH_3_OCHO) and dimethyl ether (CH_3_OCH_3_) as well as the nitrogen-bearing formamide (NH_2_CHO) and ethyl cyanide (C_2_H_5_CN), towards a large sample of 39 high-mass star-forming regions representing different evolutionary stages, from early to evolved phases. We aim to identify potential correlations and chemical links between the molecules and to trace their evolutionary sequence through the star formation process. We analysed spectra obtained at 3, 2, and 0.9mm with the IRAM-30m telescope. We derived the main physical parameters for each species by fitting the molecular lines. We compared them and evaluated their evolution while also taking several other interstellar environments into account. We report detections in 20 sources, revealing a clear dust absorption effect on column densities. Derived abundances range between ~10^-10^-10^-7^ for CH_3_OCHO and CH_3_OCH_3_, ~10^-12^-10^-10^ for NH_2_CHO, and ~10^-11^-10^-9^ for C_2_H_5_CN. The abundances of CH3OCHO, CH3OCH3, and C2H5CN are very strongly correlated (r>=0.92) across 4 orders of magnitude.We note that CH_3_OCHO and CH_3_OCH_3_ show the strongest correlations in most parameters, and a nearly constant ratio (1) over a remarkable 9 orders of magnitude in luminosity for the following wide variety of sources: pre-stellar to evolved cores, low- to high-mass objects, shocks, Galactic clouds, and comets. This indicates that COMs chemistry is likely early developed and then preserved through evolved phases. Moreover, the molecular abundances clearly increase with evolution, covering 6 orders of magnitude in the luminosity/mass ratio. We consider CH_3_OCHO and CH_3_OCH_3_ to be most likely chemically linked. They could, for example, share a common precursor, or be formed one from the other. Based on correlations, ratios, and the evolutionary trend, we propose a general scenario for all COMs, involving a formation in the cold, earliest phases of star formation and a following increasing desorption with the progressive thermal and shock-induced heating of the evolving core.
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- ID:
- ivo://CDS.VizieR/J/A+A/639/A87
- Title:
- Complex organic mol. in low-mass protostars
- Short Name:
- J/A+A/639/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Complex organic molecules (COMs) are thought to form on icy dust grains in the earliest phase of star formation. The evolution of these COMs from the youngest Class 0/I protostellar phases toward the more evolved Class II phase is still not fully understood. Since planet formation seems to start early, and mature disks are too cold for characteristic COM emission lines, studying the inventory of COMs on Solar- System scales in the Class 0/I stage is relevant. Our aim is to determine the abundance ratios of oxygen-bearing COMs in Class 0 protostellar systems on scales of ~100AU radius. We aim to compare these abundances with one another, and to the abundances of other low-mass protostars such as IRAS16293-2422B and HH 212. Additionally, using both cold and hot COM lines, the gas-phase abundances can be tracked from a cold to a hot component, and ultimately be compared with those in ices to be measured with the James Webb Space Telescope (JWST). The abundance of deuterated methanol allows us to probe the ambient temperature during the formation of this species. ALMA Band 3 (3mm) and Band 6 (1mm) observations are obtained for seven Class 0 protostars in the Perseus and Serpens star-forming regions. By modeling the inner protostellar region using local thermodynamic equilibrium (LTE) models, the excitation temperature and column densities are determined for several O-bearing COMs including methanol (CH_3_OH), acetaldehyde (CH_3_CHO), methyl formate (CH_3_OCHO), and dimethyl ether (CH_3_OCH_3_). Abundance ratios are taken with respect to CH_3_OH. Three out of the seven of the observed sources, B1-c, B1-bS (both Perseus), and Serpens S68N (Serpens), show COM emission. No clear correlation seems to exist between the occurrence of COMs and source luminosity. The abundances of several COMs such as CH_3_OCHO, CH_3_OCH_3_, acetone (CH_3_COCH_3_), and ethylene glycol ((CH_2_OH)2) are remarkably similar for the three COM-rich sources; this similarity also extends to IRAS 16238-2422B and HH 212, even though collectively these sources originate from four different star-forming regions (i.e., Perseus, Serpens, Ophiuchus, and Orion). For other COMs like CH_3_CHO, ethanol (CH_3_CH_2_OH), and glycolaldehyde (CH_2_OHCHO), the abundances differ by up to an order of magnitude, indicating that local source conditions become important. B1-c hosts a cold (Tex=60K), more extended component of COM emission with a column density of typically a few percent of the warm/hot (Tex=200K) central component. A D/H ratio of 1-3% is derived for B1-c, S68N, and B1-bS based on the CH_2_DOH/CH_3_OH ratio (taking into account statistical weighting) suggesting a temperature of ~15K during the formation of methanol. This ratio is consistent with other low-mass protostars, but is lower than for high-mass star-forming regions. The abundance ratios of most O-bearing COMs are roughly fixed between different star-forming regions, and are presumably set at an earlier cold prestellar phase. For several COMs, local source properties become important. Future mid-infrared facilities such as JWST/MIRI will be essential for the direct observation of COM ices. Combining this with a larger sample of COM-rich sources with ALMA will allow ice and gas-phase abundances to be directly linked in order to constrain the routes that produce and maintain chemical complexity during the star formation process.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/83
- Title:
- Component structure in the neightborhood of IC 443
- Short Name:
- J/ApJ/897/83
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present the results of a detailed investigation into the physical conditions in interstellar material interacting with the supernova remnant (SNR) IC443. Our analysis is based on a comprehensive examination of high-resolution far-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope of two stars behind IC443. One of our targets (HD43582) probes gas along the entire line of sight through the SNR, while the other (HD254755) samples material located ahead of the primary supernova shock front. We identify low-velocity quiescent gas in both directions and find that the densities and temperatures in these components are typical of diffuse atomic and molecular clouds. Numerous high- velocity components are observed in the absorption profiles of neutral and singly ionized atomic species toward HD43582. These components exhibit a combination of greatly enhanced thermal pressures and significantly reduced dust-grain depletions. We interpret this material as cooling gas in a recombination zone far downstream from shocks driven into neutral gas clumps. The pressures derived for a group of ionized gas components at high positive velocity toward HD43582 are lower than those of the other shocked components, pointing to pressure inhomogeneities across the remnant. A strong, very high velocity component near -620km/s is seen in the absorption profiles of highly ionized species toward HD43582. The velocity of this material is consistent with the range of shock velocities implied by observations of soft thermal X-ray emission from IC443. Moderately high velocity gas toward HD254755 may represent shocked material from a separate foreground SNR.
3224. ComPRASS catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/626/A7
- Title:
- ComPRASS catalogue
- Short Name:
- J/A+A/626/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first all-sky catalogue of galaxy clusters and cluster candidates obtained from joint X-ray-SZ detections using observations from the Planck satellite and the ROSAT all-sky survey (RASS). The catalogue contains 2323 objects and has been validated by careful cross-identification with previously known clusters. This validation shows that 1597 candidates correspond to already known clusters, 212 coincide with other cluster candidates still to be confirmed, and the remaining 514 are completely new detections. With respect to Planck catalogues, the ComPRASS catalogue is simultaneously more pure and more complete. Based on the validation results in the SPT and SDSS footprints, the expected purity of the catalogue is at least 84.5%, meaning that more than 365 clusters are expected to be found among the new or still-to-be-confirmed candidates with future validation efforts or specific follow-ups.
- ID:
- ivo://CDS.VizieR/VII/262
- Title:
- Comprehensive Catalogue of Kiso UV-X Galaxies (KUG2000)
- Short Name:
- VII/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The referenced paper describes the compilation of the second Kiso UV-Excess galaxies survey as KUG2 catalogue. The result is shown in VII/261. The first survey catalogue KUG1 is shown in VII/179. As is described in the paper, there are some differences between KUG1 and KUG2, e.g. in photographic plates used and the observation condition in the surveys, such as emulsions, exposures or seeing sizes. The homogeneity of these KUG surveys is rather low, but their catalogues form a somewhat large collection of UV-excess/blue galaxies. In these circumstances, we intend to merge both catalogues, upon requests from investigators working in follow-up observations of these galaxies. In the process of catalogue merging, we met a systematic difference between the first (KUG1) and the second (KUG2) surveys in overall properties of objects, such as brightness, degree of UV-excess and morphological type. This mainly originates from differences in the observation condition and personal errors in the survey. We scrutinize and discuss those differences and errors, and finally merge into a comprehensive catalogue of KUGs (KUG2000) in the machine-readable form including near ten thousand UV-excess galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/815/L13
- Title:
- Compton-thick AGNs from the 70-month Swift/BAT cat.
- Short Name:
- J/ApJ/815/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Heavily obscured accretion is believed to represent an important stage in the growth of supermassive black holes and to play an important role in shaping the observed spectrum of the cosmic X-ray background. Hard X-ray (E>10keV) selected samples are less affected by absorption than samples selected at lower energies, and are therefore one of the best ways to detect and identify Compton-thick (CT, logN_H_>=24) active galactic nuclei (AGNs). In this letter we present the first results of the largest broadband (0.3-150keV) X-ray spectral study of hard X-ray selected AGNs to date, focusing on the properties of heavily obscured sources. Our sample includes the 834 AGNs (728 non-blazar, average redshift z~0.055) reported in the 70-month catalog of the all-sky hard X-ray Swift/Burst Alert Monitor survey. We find 55 CT AGNs, which represent 7.6_-2.1_^+1.1^% of our non-blazar sample. Of these, 26 are reported as candidate CT AGNs for the first time. We correct for selection bias and derive the intrinsic column density distribution of AGNs in the local universe in two different luminosity ranges. We find a significant decrease in the fraction of obscured Compton-thin AGNs for increasing luminosity, from 46+/-3% (for logL_14-195_=40-43.7) to 39+/-3% (for logL_14-195_=43.7-46). A similar trend is also found for CT AGNs. The intrinsic fraction of CT AGNs with logN_H_=24-25 normalized to unity in the logN_H_=20-25 range is 27+/-4%, and is consistent with the observed value obtained for AGNs located within 20Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/148
- Title:
- Concentration-mass relation for XXL clusters
- Short Name:
- J/ApJ/890/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a weak-lensing analysis of X-ray galaxy groups and clusters selected from the XMM-XXL survey using the first-year data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program. Our joint weak-lensing and X-ray analysis focuses on 136 spectroscopically confirmed X-ray-selected systems at 0.031<=z<=1.033 detected in the 25deg^2^ XXL-N region, which largely overlaps with the HSC-XMM field. With high-quality HSC weak-lensing data, we characterize the mass distributions of individual clusters and establish the concentration-mass (c-M) relation for the XXL sample, by accounting for selection bias and statistical effects and marginalizing over the remaining mass calibration uncertainty. We find the mass-trend parameter of the c-M relation to be {beta}=-0.07+/-0.28 and the normalization to be c_200_=4.8+/-1.0(stat)+/-0.8(syst) at M_200_=10^14^h^-1^M_{sun}_ and z=0.3. We find no statistical evidence for redshift evolution. Our weak-lensing results are in excellent agreement with dark-matter-only c-M relations calibrated for recent {Lambda}CDM cosmologies. The level of intrinsic scatter in c200 is constrained as {sigma}(lnc_200_)<24% (99.7% CL), which is smaller than predicted for the full population of {Lambda}CDM halos. This is likely caused in part by the X-ray selection bias in terms of the cool-core or relaxation state. We determine the temperature-mass (T_X_-M_500_) relation for a subset of 105 XXL clusters that have both measured HSC lensing masses and X-ray temperatures. The resulting TX-M500 relation is consistent with the self-similar prediction. Our TX-M500 relation agrees with the XXL DR1 results at group scales but has a slightly steeper mass trend, implying a smaller mass scale in the cluster regime. The overall offset in the TX-M500 relation is at the ~1.5{sigma} level, corresponding to a mean mass offset of 34%+/-20%. We also provide bias-corrected, weak-lensing-calibrated M200 and M500 mass estimates of individual XXL clusters based on their measured X-ray temperatures.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/1917
- Title:
- Concentration parameter of galaxy clusters
- Short Name:
- J/MNRAS/468/1917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterized the population of galaxy clusters detected with the Sunyaev-Zeldovich (SZ) effect with Planck by measuring the cool-core state of the objects in a well-defined subsample of the Planck SZ catalogue. We used as an indicator the concentration parameter. The fraction of cool-core clusters is 29+/-4 per cent and does not show significant indications of evolution in the redshift range covered by our sample. We compare the distribution of the concentration parameter in the Planck sample with the one of the X-ray selected sample MACS: the distributions are significantly different and the cool-core fraction in MACS is much higher (59+/-5 per cent) than that in Planck. Since X-ray-selected samples are known to be biased towards cool cores due to the presence of their prominent surface brightness peak, we simulated the impact of the 'cool-core bias'. We found that this bias plays a large role in the difference between the fractions of cool cores in the two samples. We examined other selection effects that could in principle bias SZ surveys against cool cores, but we found that their impact is not sufficient to explain the difference between Planck and MACS. The population of X-ray underluminous objects, which are found in SZ surveys but missing in X-ray samples, could possibly contribute to the difference, as we found most of them to be non-cool cores, but this hypothesis deserves further investigation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2561
- Title:
- CONCH-SHELL catalog of nearby M dwarfs
- Short Name:
- J/MNRAS/443/2561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky catalogue of 2970 nearby (d<~50pc), bright (J<9) M- or late K-type dwarf stars, 86% of which have been confirmed by spectroscopy. This catalogue will be useful for searches for Earth-size and possibly Earth-like planets by future space-based transit missions and ground-based infrared Doppler radial velocity surveys. Stars were selected from the SUPERBLINK proper motion catalogue (Cat. I/298) according to absolute magnitudes, spectra, or a combination of reduced proper motions and photometric colours. From our spectra, we determined gravity-sensitive indices, and identified and removed 0.2% of these as interloping hotter or evolved stars. 13% of the stars exhibit H{alpha} emission, an indication of stellar magnetic activity and possible youth. The mean metallicity is [Fe/H]=-0.07 with a standard deviation of 0.22dex, similar to nearby solar-type stars. We determined stellar effective temperatures by least-squares fitting of spectra to model predictions calibrated by fits to stars with established bolometric temperatures, and estimated radii, luminosities, and masses using empirical relations. 6% of stars with images from integral field spectra are resolved doubles. We inferred the planet population around M dwarfs using Kepler data and applied this to our catalogue to predict detections by future exoplanet surveys.
- ID:
- ivo://xcatdb/xidresult/cs
- Title:
- Cone Search of the XMM-Newton Optical Follow-up results database (XIDResult)
- Short Name:
- XIDResult
- Date:
- 04 Mar 2021 10:29:24
- Publisher:
- Observatory of Strasbourg, SSC Team
- Description:
- The SSC's XID programme is a follow-up and identification project designed to ensure that the potential of the XMM-Newton serendipitous survey can be exploited by the community in the context of a wide range of scientific programmes. Its main elements are a number of complementary sub-programmes designed to obtain the identifications for well-defined samples of X-ray sources drawn from selected XMM-Newton fields using optical/IR spectroscopy. The programme is also supported by a substantial imaging programme, needed for the selection of the spectroscopic targets, but which is also an important resource in its own right given the large sky area and hence X-ray source sample it covers. One of the principal objectives of the programme is to obtain completely identified samples which can be used to characterise the overall XMM-Newton source population sufficiently well that the basic X-ray and optical parameters can be used to assign a statistical identification for a large fraction of all the sources in the XMM-Newton serendipitous source catalogue. The XID programme started in mid-2000. Most of the programme is now complete. The XIDResult Database collects together the main results from the XID programme in a uniform way, providing access to the individual source identifications and the key optical and X-ray data for each object. Currently in the XIDResult Database contains 3 key XID programme subsamples, the XBS (XID bright flux sample), the XMS (XID medium flux sample) and the GPS (Galactic source sample), all of which have been published or are in press. The main references for each of these subsamples are as follows: * XBS: Caccianiga et al. 2008, A&A 477, 735 (400 sources, 238 spectra) * XMS: Barcons et al. 2007, A&A 476, 1191 (319 sources, 280 spectra) * GPS: Motch et al. 2010, A&A in press (43 sources, 27 spectra)