- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2025
- Title:
- HIPASS-ZoA HII regions
- Short Name:
- J/MNRAS/450/2025
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Radio Recombination Line (RRL) survey of the Galactic plane from the Hi Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196{deg}-0{deg}-52{deg} and |b|<=5{deg} at 1.4GHz and 14.4-arcmin resolution. We combine three RRLs, H168{alpha}, H167{alpha}, and H166{alpha} to derive fully sampled maps of the diffuse ionized emission along the inner Galactic plane. The velocity information, at a resolution of 20km/s, allows us to study the spatial distribution of the ionized gas and compare it with that of the molecular gas, as traced by CO. The longitude-velocity diagram shows that the RRL emission is mostly associated with CO gas from the molecular ring and is concentrated within the inner 30{deg} of longitude. A map of the free-free emission in this region of the Galaxy is derived from the line-integrated RRL emission, assuming an electron temperature gradient with Galactocentric radius of 496+/-100K/kpc. Based on the thermal continuum map, we extracted a catalogue of 317 compact (<~15-arcmin) sources, with flux densities, sizes, and velocities. We report the first RRL observations of the southern ionized lobe in the Galactic Centre. The line profiles and velocities suggest that this degree-scale structure is in rotation. We also present new evidence of diffuse ionized gas in the 3-kpc arm. Helium and carbon RRLs are detected in this survey. The He line is mostly observed towards HII regions, whereas the C line is also detected further away from the source of ionization. These data represent the first observations of diffuse C RRLs in the Galactic plane at a frequency of 1.4GHz.
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652. HI survey of AGNs
- ID:
- ivo://CDS.VizieR/J/ApJS/177/103
- Title:
- HI survey of AGNs
- Short Name:
- J/ApJS/177/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a new Arecibo survey for HI emission for 113 galaxies with broad-line (type 1) active galactic nuclei (AGNs) out to recession velocities as high as ~35000km/s. The primary aim of the study is to obtain sensitive HI spectra for a well-defined, uniformly selected sample of active galaxies that have estimates of their black hole masses in order to investigate correlations between HI properties and the characteristics of the AGNs. HI emission was detected in 66 out of the 101 (65%) objects with spectra uncorrupted by radio frequency interference, among which 45 (68%) have line profiles with adequate signal-to-noise ratio and sufficiently reliable inclination corrections to yield robust deprojected rotational velocities. This paper presents the basic survey products, including an atlas of HI spectra, measurements of HI flux, line width, profile asymmetry, optical images, optical spectroscopic parameters, as well as a summary of a number of derived properties pertaining to the host galaxies. To enlarge our primary sample, we also assemble all previously published HI measurements of type 1 AGNs for which we can estimate black hole masses, which total an additional 53 objects. The final comprehensive compilation of 154 broad-line active galaxies, by far the largest sample ever studied, forms the basis of our companion paper, which uses the HI database to explore a number of properties of the AGN host galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/386/140
- Title:
- HI survey of polar ring galaxies. IV.
- Short Name:
- J/A+A/386/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 33 polar ring galaxies and polar ring galaxy candidates were observed in the 21-cm HI line with the 64-m Parkes radio telescope. The objects, selected by their optical morphology, are all south of declination -39{deg} and in only 5 of them had been reported previously. HI line emission was detected towards 18 objects, though in 3 cases the detection may be confused by another galaxy in the telescope beam, and one is a marginal detection. Eight objects were detected for the first time in HI, of which 5 did not have previously known redshifts.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A120
- Title:
- HL TAU and IRAS04302+2247 H2CS ALMA images
- Short Name:
- J/A+A/644/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planet formation starts around Sun-like protostars with ages <=1Myr, but the chemical compositions of the surrounding discs remains unknown. We aim to trace the radial and vertical spatial distribution of a key species of S-bearing chemistry, namely H_2_CS, in protoplanetary discs. We also aim to analyse the observed distributions in light of the H_2_CS binding energy in order to discuss the role of thermal desorption in enriching the gas disc component. In the context of the ALMA chemical survey of disk-outflow sources in the Taurus star forming region (ALMA-DOT), we observed five Class I or early Class II sources with the o-H_2_CS(7_1,6_-6_1,5_) line. ALMA-Band 6 was used, reaching spatial resolutions ~=40au, that is, Solar System spatial scales. We also estimated the binding energy of H2CS using quantum mechanical calculations, for the first time, for an extended, periodic, crystalline ice. We imaged H2CS emission in two rotating molecular rings in the HL Tau and IRAS04302+2247 discs, the outer radii of which are ~140au (HL Tau) and 115 au (IRAS 04302+2247). The edge-on geometry of IRAS 04302+2247 allows us to reveal that H2CS emission peaks at radii of 60-115au, at z=+/-50au from the equatorial plane. Assuming LTE conditions, the column densities are 10^14^cm^-2^. We estimate upper limits of a few 10^13^cm^-2^ for the H2CS column densities in DG Tau, DG Tau B, and Haro 6-13 discs. For HL Tau, we derive, for the first time, the [H_2_CS]/[H] abundance in a protoplanetary disc (~10^-14^). The binding energy of H2CS computed for extended crystalline ice and amorphous ices is 4258K and 3000-4600K, respectively, implying thermal evaporation where dust temperatures are 50-80K. H_2_CS traces the so-called warm molecular layer, a region previously sampled using CS and H_2_CO. Thioformaldehyde peaks closer to the protostar than H_2_CO and CS, plausibly because of the relatively high excitation level of the observed 7_1,6_-6_1,5_ line (60K). The H_2_CS binding energy implies that thermal desorption dominates in thin, au-sized, inner and/or upper disc layers, indicating that the observed H2CS emitting up to radii larger than 100au is likely injected in the gas phase due to non-thermal processes.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A104
- Title:
- HL Tau SO2 14(0-14)-13(1,13) datacube
- Short Name:
- J/A+A/658/A104
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Planet-forming disks are not isolated systems. Their interaction with the surrounding medium affects their mass budget and chemical content. In the context of the ALMA-DOT program, we obtained high-resolution maps of assorted lines from six disks that are still partly embedded in their natal envelope. In this work, we examine the SO and SO_2_ emission that is detected from four sources: DG Tau, HL Tau, IRAS 04302+2247, and T Tau. The comparison with CO, HCO^+^, and CS maps reveals that the SO and SO_2_ emission originates at the intersection between extended streamers and the planet-forming disk. Two targets, DG Tau and HL Tau, offers clear cases of inflowing material inducing an accretion shock on the disk material. The measured rotational temperatures and radial velocities are consistent with this view. In contrast to younger Class 0 sources, these shocks are confined to the specific disk region impacted by the streamer. In HL Tau, the known accreting streamer induces a shock in the disk outskirt, and the released SO and SO_2_ molecules spiral toward the star in a few hundreds years. These results suggest that shocks induced by late accreting material may be common in the disks of young star-forming regions with possible consequences on the chemical composition and mass content of the disk. They also highlight the importance of SO and SO_2_ line observations to probe accretion shocks from a larger sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/82
- Title:
- H_2_ masses in a broad sample of galaxies
- Short Name:
- J/ApJ/769/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To assess how external factors such as local interactions and fresh gas accretion influence the global interstellar medium of galaxies, we analyze the relationship between recent enhancements of central star formation and total molecular-to-atomic (H_2_/HI) gas ratios, using a broad sample of field galaxies spanning early-to-late type morphologies, stellar masses of 10^7.2^-10^11.2^M_{sun}_, and diverse stages of evolution. We find that galaxies occupy several loci in a "fueling diagram" that plots H_2_/HI ratio versus mass-corrected blue-centeredness, a metric tracing the degree to which galaxies have bluer centers than the average galaxy at their stellar mass. Spiral galaxies of all stellar masses show a positive correlation between H_2_/HI ratio and mass-corrected blue-centeredness. When combined with previous results linking mass-corrected blue-centeredness to external perturbations, this correlation suggests a systematic link between local galaxy interactions and molecular gas inflow/replenishment. Intriguingly, E/S0 galaxies show a more complex picture: some follow the same correlation, some are quenched, and a distinct population of blue-sequence E/S0 galaxies (with masses below key scales associated with transitions in gas richness) defines a separate loop in the fueling diagram. This population appears to be composed of low-mass merger remnants currently in late- or post-starburst states, in which the burst first consumes the H_2_ while the galaxy center keeps getting bluer, then exhausts the H_2_, at which point the burst population reddens as it ages. Multiple lines of evidence suggest connected evolutionary sequences in the fueling diagram. In particular, tracking total gas-to-stellar mass ratios within the fueling diagram provides evidence of fresh gas accretion onto low-mass E/S0s emerging from their central starburst episodes. Drawing on a comprehensive literature search, we suggest that virtually all galaxies follow the same evolutionary patterns found in our broad sample.
- ID:
- ivo://CDS.VizieR/J/A+A/361/1079
- Title:
- HNCO in massive galactic dense cores
- Short Name:
- J/A+A/361/1079
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed 81 dense molecular cores associated with regions of massive star formation and Sgr A in the J_(K_-1_K_1_)=5_(05)-4_(04)_ and 10_(010)-9_(09)_ lines of HNCO. Line emission was detected towards 57 objects. Selected subsamples were also observed in the 1_(01)-0_(00)_, 4_(04)-3_(03)_, 7_(07)-6_(06)_, 15_(015)-14_(014)_, 16_(016)-15_(015)_ and 21_(021)-20_(020)_ lines, covering a frequency range from 22 to 461 GHz. HNCO lines from the K_(-1)=2,3 ladders were detected in several sources. Towards Orion-KL, K_(-1)=5 transitions with upper state energies E_u/k~1100 and 1300K could be observed. The tables contain the source lists and the results of these SEST observations.
- ID:
- ivo://CDS.VizieR/J/A+A/391/967
- Title:
- H2O and SiO masers in the Galactic center
- Short Name:
- J/A+A/391/967
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed targeted surveys for 22GHz H_2_O and 43GHz SiO maser emission in Galactic center OH/IR stars using the Very Large Array. Some of the detections have been used in a previous paper to investigate the possibility of measuring milli-arcsecond accurate positions (to obtain stellar proper motions) in the Galactic center. Here we report on the detection of at least 25 H_2_O masers and 18 SiO masers associated with stars within 2{deg} and 15' of Sgr A*, respectively. This survey has more than doubled the total number of proper motion candidates to at least about 50 stellar objects.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/25
- Title:
- H_2_O + CH_3_OH maser survey of Orion protostars
- Short Name:
- J/ApJS/209/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a maser survey toward 99 protostars in the Orion molecular cloud complex are presented. The target sources are low-mass protostars identified from infrared observations. Single-dish observations were carried out in the water maser line at 22GHz and the methanol class I maser lines at 44, 95, and 133GHz. Most of the detected sources were mapped to determine the source positions. Five water maser sources were detected, and they are excited by HH 1-2 VLA 3, HH 1-2 VLA 1, L1641N MM1/3, NGC 2071 IRS 1/3, and an object in the OMC 3 region. The water masers showed significant variability in intensity and velocity with time scales of 1 month or shorter. Four methanol emission sources were detected, and those in the OMC 2 FIR 3/4 and L1641N MM1/3 regions are probably masers. The methanol emission from the other two sources in the NGC 2071 IRS 1-3 and V380 Ori NE regions are probably thermal. For the water masers, the number of detections per protostar in the survey region is about 2%, which suggests that the water masers of low-mass protostars are rarely detectable. The methanol class I maser of low-mass protostars is an even rarer phenomenon, with a detection rate much smaller than 1%.
- ID:
- ivo://CDS.VizieR/J/ApJ/658/1096
- Title:
- H2O maser classification
- Short Name:
- J/ApJ/658/1096
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 22GHz H2O maser observations of a sample of 85 post-asymptotic giant branch (post-AGB) candidate stars, selected on the basis of their OH 1612MHz maser and far-infrared properties. All sources were observed with the Tidbinbilla 70m radio telescope, and 21 detections were made; 86GHz SiO Mopra observations of a subset of the sample are also presented.