- ID:
- ivo://CDS.VizieR/J/A+A/653/A108
- Title:
- Globules and pillars in Cygnus X
- Short Name:
- J/A+A/653/A108
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- IRAS 20319+3958 in Cygnus X South is a rare example of a free-floating globule (mass ~240M_{sun}_, length ~1.5pc) with an internal HII region created by the stellar feedback of embedded intermediate-mass stars, in particular, one Herbig Be star. In Schneider et al. (2012A&A...542L..18S) and Djupvik et al. (2017A&A...599A..37D, Cat. J/A+A/599/A37), we proposed that the emission of the far-infrared (FIR) lines of [CII] at 158um and [OI] at 145um in the globule head are mostly due to an internal photodissociation region (PDR). Here, we present a Herschel/HIFI [CII] 158um map of the whole globule and a large set of other FIR lines (mid-to high-J CO lines observed with Herschel/PACS and SPIRE, the [OI] 63um line and the ^12^CO 16->15 line observed with upGREAT on SOFIA), covering the globule head and partly a position in the tail. The [CII] map revealed that the whole globule is probably rotating. Highly collimated, high-velocity [CII] emission is detected close to the Herbig Be star. We performed a PDR analysis using the KOSMA-{tau}PDR code for one position in the head and one in the tail. The observed FIR lines in the head can be reproduced with a two-component model: an extended, non-clumpy outer PDR shell and a clumpy, dense, and thin inner PDR layer, representing the interface between the HII region cavity and the external PDR. The modelled internal UV field of ~2500Go is similar to what we obtained from the Herschel FIR fluxes, but lower than what we estimated from the census of the embedded stars. External illumination from the ~30pc distant Cyg OB2 cluster, producing an UV field of ~150-600Go as an upper limit, is responsible for most of the [CII] emission. For the tail, we modelled the emission with a non-clumpy component, exposed to a UV-field of around 140Go.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/569/A110
- Title:
- GMOS-IFU spectroscopy of dwarf galaxy HS 2236+1344
- Short Name:
- J/A+A/569/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main goal of this study is to carry out a spatially resolved investigation of the warm interstellar medium (ISM) in the extremely metal-poor blue compact dwarf galaxy HS 2236+1344. Special emphasis is laid on the analysis of the spatial distribution of chemical abundances, emission-line ratios and kinematics of the ISM, and to the recent star-forming activity in this galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A49
- Title:
- G35.20-0.74N VLA continuum images
- Short Name:
- J/A+A/593/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atacama Large Millimeter/submillimeter Array (ALMA) observations of the high-mass star-forming region G35.20-0.74N have revealed the presence of a Keplerian disk in core B rotating about a massive object of 18M_{sun}_, as computed from the velocity field. The luminosity of such a massive star would be comparable to (or higher than) the luminosity of the whole star-forming region. To solve this problem it has been proposed that core B could harbor a binary system. This could also explain the possible precession of the radio jet associated with this core, which has been suggested by its S-shaped morphology. We establish the origin of the free-free emission from core B and investigate the existence of a binary system at the center of this massive core and the possible precession of the radio jet. We carried out VLA continuum observations of G35.20-0.74N at 2cm in the B configuration and at 1.3cm and 7mm in the A and B configurations. The bandwidth at 7mm covers the CH3OH maser line at 44.069GHz. Continuum images at 6 and 3.6cm in the A configuration were obtained from the VLA archive. We also carried out VERA observations of the H_2_O maser line at 22.235GHz.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A12
- Title:
- Grid of Lya radiation transfer models
- Short Name:
- J/A+A/531/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ly{alpha} is a key diagnostic for numerous observations of distant star-forming galaxies, but detailed radiation transfer models are required for interpreting them. We provide an extensive grid of 3D radiation transfer models that simulate the Ly{alpha} and UV continuum radiation transfer in the interstellar medium of star-forming galaxies. We have improved our Monte Carlo MCLya code and used it to compute a grid of 6240 radiation transfer models for homogeneous spherical shells containing HI and dust surrounding a central source. The simulations cover a wide range of parameter space. We present the detailed predictions from our models including in particular the Ly{alpha} escape fraction fesc, the continuum attenuation, and detailed Ly{alpha} line profiles. The Ly{alpha} escape fraction is shown to depend strongly on dust content, but also on other parameters (HI column density and radial velocity). The predicted line profiles show a wide diversity of morphologies, ranging from broad absorption lines to emission lines with complex features. The results from our simulations are distributed in electronic format. Our models should be of use for interpreting observations from distant galaxies, for other simulations, and should also serve as an important basis for comparison for future, more refined, radiation transfer models.
- ID:
- ivo://CDS.VizieR/J/ApJ/647/418
- Title:
- Ground-state OH masers in W3(OH) study
- Short Name:
- J/ApJ/647/418
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VLBA observations of the ground-state hydroxyl masers in W3(OH) at 0.02km/s spectral resolution. Over 250 masers are detected, including 56 Zeeman pairs. Line shapes are predominantly Gaussian or combinations of several Gaussians, with normalized deviations typically of the same magnitude as in masers in other species.
- 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/A+A/624/A138
- Title:
- G09v1.97 CO and H2O datacubes
- Short Name:
- J/A+A/624/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Atacama Large Millimeter/submillimeter Array (ALMA), we report high angular-resolution observations of the redshift z=3.63 galaxy H-ATLAS J083051.0+013224 (G09v1.97), one of the most luminous strongly lensed galaxies discovered by the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). We present 0.2"-0.4" resolution images of the rest-frame 188 and 419um dust continuum and the CO(6-5), H_2_O(2_11_-2_02_), and Jup=2H_2_O^+^ line emission. We also report the detection of H_2_^18^O(2_11_-2_02_) in this source. The dust continuum and molecular gas emission are resolved into a nearly complete ~1.5" diameter Einstein ring plus a weaker image in the center, which is caused by a special dual deflector lensing configuration. The observed line profiles of the CO(6-5), H_2_O(2_11_-2_02_), and Jup=2H_2_O^+^ lines are strikingly similar. In the source plane, we reconstruct the dust continuum images and the spectral cubes of the CO, H_2_O, and H_2_O^+^ line emission at sub-kiloparsec scales. The reconstructed dust emission in the source plane is dominated by a compact disk with an effective radius of 0.7+/-0.1kpc plus an overlapping extended disk with a radius twice as large. While the average magnification for the dust continuum is {mu}~10-11, the magnification of the line emission varies from 5 to 22 across different velocity components. The line emission of CO(6-5), H_2_O(2_11_-2_02_), and H_2_O^+^ have similar spatial and kinematic distributions. The molecular gas and dust content reveal that G09v1.97 is a gas-rich major merger in its pre-coalescence phase, with a total molecular gas mass of ~10^11^M_{sun}_. Both of the merging companions are intrinsically ultra-luminous infrared galaxies (ULIRGs) with infrared luminosities LIR reaching 4x10^12^L_{sun}_, and the total LIR of G09v1.97 is (1.4+/-0.7)x10^13^L_{sun}_. The approaching southern galaxy (dominating from V=-400 to -150km/s relative to the systemic velocity) shows no obvious kinematic structure with a semi-major half-light radius of a_s_=0.4kpc, while the receding galaxy (0 to 350km/s) resembles an a_s_=1.2kpc rotating disk. The two galaxies are separated by a projected distance of 1.3kpc, bridged by weak line emission (-150 to 0km/s) that is co-spatially located with the cold dust emission peak, suggesting a large amount of cold interstellar medium (ISM) in the interacting region. As one of the most luminous star-forming dusty high-redshift galaxies, G09v1.97 is an exceptional source for understanding the ISM in gas-rich starbursting major merging systems at high redshift.
- ID:
- ivo://CDS.VizieR/J/other/NatAs/4.1072
- Title:
- HaloSat survey of southern Galactic halo
- Short Name:
- J/other/NatAs/4.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near 2x10^6^K studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of ~10 degrees indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.
- ID:
- ivo://CDS.VizieR/J/A+A/470/605
- Title:
- Halpha and [SII] images in HL/XZ Tau region
- Short Name:
- J/A+A/470/605
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we investigated the environment of HL/XZ Tau, which contains a compact and very active nest of YSOs. We explore the kinematic properties of the close association of jets in this region and study the interaction of jets with the ambient medium, as well as the outflows with each other. The scanning Fabry-Perot interferometry of the HL/XZ Tau region in H{alpha} and [SII] 6716{AA} emission lines was performed. We also measure the proper motions of the knots in the outflows, as derived from images obtained in 1997 and 2001, to achieve the full 3D kinematic picture.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A176
- Title:
- Halpha+[NII] imaging of Dorado galaxies
- Short Name:
- J/A+A/643/A176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dorado is a nearby, rich and clumpy galaxy group that extends for several degrees in the Southern Hemisphere. Although several studies have been dedicated to define its members, their kinematics, hot and cold gas content, in particular HI, their present star formation activity is yet unknown. For the first time, we map the H{alpha} distribution as a possible indicator of star formation activity of Dorado members a large fraction of which show interaction and merging signatures, regardless of their morphological type. With the 2.5m du Pont and the 1m Swope telescopes we obtained narrow-band, calibrated images of 14 galaxies, forming the backbone of the group, mapping H{alpha}+[NII] down to few 10^-17^erg/cm^2^/s/arcsec^2^. We estimated the galaxy star formation rate from the H{alpha} fluxes, corrected for Galaxy foreground extinction and [NII] contamination. H{alpha}+[NII] emission has been detected in all galaxies. HII regions clearly emerge in late-type galaxies, while in early-type galaxies the H{alpha}+[NII] emission is dominated by [NII], especially in the central regions. However, HII complexes are revealed in four early-type galaxies. Even in the compact group SGC 0414-5559, in the projected centre of Dorado, HII regions are found both through out the late-type galaxies and in the very outskirts of early-type members. Considering the Dorado group as a whole, we notice that the H{alpha}+[NII] equivalent width, a measure of the specific star formation, increases with the morphological type, from early to late-type members, although it remains lower that what observed in similar surveys of spiral galaxies. The star formation rate of the spiral members is in the range of what observed in similar galaxies surveys (James et al., 2004A&A...414...23J, Cat. J/A+A/414/23). However, in three spiral NGC 1536, PGC 75125 and IC 2058 the star formation rate is well below the median for their morphological classes. The star formation rate of some early-type members tends, at odds, to be higher than the average derived from H{alpha}+[NII] surveys of this morphological family. We detected in H{alpha}+[NII] all the early type galaxies observed and half of them show HII regions in well shaped rings as well as in their outskirts. These findings suggest that ETGs in this group are not dead galaxies: their star formation has not shutdown yet. Mechanisms such as gas stripping and gas accretion, through galaxy-galaxy interaction, seem relevant in modifying star formation in this evolutionary phase of Dorado.
