scholarly journals Different evolutionary stages in S235A-B

2006 ◽  
Vol 2 (S237) ◽  
pp. 412-412
Author(s):  
Marcello Felli ◽  
Fabrizio Massi ◽  
Riccardo Cesaroni

AbstractThe star forming region S235A-B has been studied at high resolution with radio (IRAM Interferometer and VLA) and infrared (JCMT and Spitzer) observations. The region was mapped in HCO+, C34S, H2CS, SO2 and CH3CN as well as in the 1.2 and 3.3 continuum, in the cm continuum at 6, 3.6, 1.3 and 0.7 cm and in the 22 GHz water maser line, in the far infrared at 450 and 850 μm and in the mid infrared from 3.6 to 8 μm. Finally, use was made of the Medicina water maser patrol, from 1987 to 2005, to study the maser variability.

2001 ◽  
Vol 553 (1) ◽  
pp. 254-266 ◽  
Author(s):  
Yoshiko K. Okamoto ◽  
Hirokazu Kataza ◽  
Takuya Yamashita ◽  
Takashi Miyata ◽  
Takashi Onaka

1995 ◽  
Vol 452 ◽  
pp. 308 ◽  
Author(s):  
C. Y. Zhang ◽  
P. M. Harvey ◽  
Beverly J. Smith ◽  
C. Colome ◽  
J. Difrancesco

2020 ◽  
Vol 493 (3) ◽  
pp. 4442-4452 ◽  
Author(s):  
M S Darwish ◽  
K A Edris ◽  
A M S Richards ◽  
S Etoka ◽  
M S Saad ◽  
...  

ABSTRACT We investigate the kinematics of high-mass protostellar objects within the high-mass star-forming region IRAS 19410+2336. We performed high angular resolution observations of 6.7-GHz methanol and 22 GHz water masers using the Multi-Element Radio Linked Interferometer Network (MERLIN) and e-MERLIN interferometers. The 6.7-GHz methanol maser emission line was detected within the ∼16–27 km s−1 velocity range with a peak flux density ∼50 Jy. The maser spots are spread over ∼1.3 arcsec on the sky, corresponding to ∼2800 au at a distance of 2.16 kpc. These are the first astrometric measurements at 6.7 GHz in IRAS 19410+2336. The 22-GHz water maser line was imaged in 2005 and 2019 (the latter with good astrometry). Its velocities range from 13 to ∼29 km s−1. The peak flux density was found to be 18.7 and 13.487 Jy in 2005 and 2019, respectively. The distribution of the water maser components is up to 165 mas, ∼350 au at 2.16 kpc. We find that the Eastern methanol masers most probably trace outflows from the region of millimetre source mm1. The water masers to the West lie in a disc (flared or interacting with outflow/infall) around another more evolved millimetre source (13-s). The maser distribution suggests that the disc lies at an angle of 60° or more to the plane of the sky and the observed line-of-sight velocities then suggest an enclosed mass between 44 M⊙ and as little as 11 M⊙ if the disc is edge-on. The Western methanol masers may be infalling.


2018 ◽  
Vol 07 (04) ◽  
pp. 1840015 ◽  
Author(s):  
Samuel N. Richards ◽  
Samuel H. Moseley ◽  
Gordon Stacey ◽  
Matthew Greenhouse ◽  
Alexander Kutyrev ◽  
...  

The HIgh-Resolution Mid-infrarEd Spectrometer (HIRMES) is the 3rd Generation Instrument for the Stratospheric Observatory For Infrared Astronomy (SOFIA), currently in development at the NASA Goddard Space Flight Center (GSFC), and due for commissioning in 2019. By combining direct-detection Transition Edge Sensor (TES) bolometer arrays, grating-dispersive spectroscopy, and a host of Fabry-Perot tunable filters, HIRMES will provide the ability for high resolution ([Formula: see text]), mid-resolution ([Formula: see text]), and low-resolution ([Formula: see text]) slit-spectroscopy, and 2D Spectral Imaging ([Formula: see text] at selected wavelengths) over the 25–122[Formula: see text][Formula: see text]m mid to far infrared waveband. The driving science application is the evolution of proto-planetary systems via measurements of water-vapor, water-ice, deuterated hydrogen (HD), and neutral oxygen lines. However, HIRMES has been designed to be as flexible as possible to cover a wide range of science cases that fall within its phase-space, all whilst reaching sensitivities and observing powers not yet seen thus far on SOFIA, providing unique observing capabilities which will remain unmatched for decades.


2017 ◽  
Vol 13 (S332) ◽  
pp. 270-273 ◽  
Author(s):  
Igor Zinchenko ◽  
Sheng-Yuan Liu ◽  
Yu-Nung Su ◽  
Petr Zemlyanukha

AbstractWe present preliminary results of the high resolution (0.10″ × 0.15″) observations of the high mass star forming region S255IR with ALMA in several spectral windows from ∼335 GHz to ∼350 GHz. The main target lines were C34S(7–6), CH3CN(19K − 18K), CO(3–2) and SiO(8–7), however many other lines of various molecules have been detected, too. We present sample spectra and maps, discuss briefly the source structure and kinematics. A new, never predicted methanol maser line has been discovered.


2019 ◽  
Vol 490 (4) ◽  
pp. 4956-4974 ◽  
Author(s):  
B Gullberg ◽  
Ian Smail ◽  
A M Swinbank ◽  
U Dudzevičiūtė ◽  
S M Stach ◽  
...  

ABSTRACT We present an analysis of the morphology and profiles of the dust continuum emission in 153 bright sub-millimetre galaxies (SMGs) detected with ALMA at signal-to-noise ratios of >8 in high-resolution 0.18 arcsec (∼1 kpc) 870 $\mu$m maps. We measure sizes, shapes, and light profiles for the rest-frame far-infrared emission from these luminous star-forming systems and derive a median effective radius (Re) of 0.10 ± 0.04 arcsec for our sample with a median flux of S870 = 5.6 ± 0.2 mJy. We find that the apparent axial ratio (b/a) distribution of the SMGs peaks at b/a ∼ 0.63 ± 0.02 and is best described by triaxial morphologies, while their emission profiles are best fitted by a Sérsic model with n ≃ 1.0 ± 0.1, similar to exponential discs. This combination of triaxiality and n ∼ 1 Sérsic index are characteristic of bars and we suggest that the bulk of the 870 $\mu$m dust continuum emission in the central ∼2 kpc of these galaxies arises from bar-like structures. As such we caution against using the orientation of shape of the bright dust continuum emission at $\eqsim$ resolution to assess either the orientation of any disc on the sky or tits inclination. By stacking our 870 $\mu$m maps we recover faint extended dust continuum emission on ∼4 kpc scales which contributes 13 ± 1 per cent of the total 870 $\mu$m emission. The scale of this extended emission is similar to that seen for the molecular gas and rest-frame optical light in these systems, suggesting that it represents an extended dust and gas disc at radii larger than the more active bar component. Including this component in our estimated size of the sources we derive a typical effective radius of ≃0.15 ± 0.05 arcsec or 1.2 ± 0.4 kpc. Our results suggest that kpc-scale bars are ubiquitous features of high star-formation rate systems at $z$ ≫ 1, while these systems also contain fainter and more extended gas and stellar envelopes. We suggest that these features, seen some 10–12 Gyr ago, represent the formation phase of the earliest galactic-scale components: stellar bulges.


2002 ◽  
Vol 4 ◽  
pp. 333-333
Author(s):  
S. K. Ghosh ◽  
D. K. Ojha ◽  
R. P. Verma

2020 ◽  
Vol 124 (12) ◽  
pp. 2427-2435 ◽  
Author(s):  
Marie-Aline Martin-Drumel ◽  
Jessica P. Porterfield ◽  
Manuel Goubet ◽  
Pierre Asselin ◽  
Robert Georges ◽  
...  

2020 ◽  
Vol 15 (S359) ◽  
pp. 17-21
Author(s):  
Karín Menéndez-Delmestre ◽  
Laurie Riguccini ◽  
Ezequiel Treister

AbstractThe coexistence of star formation and AGN activity has geared much attention to dusty galaxies at high redshifts, in the interest of understanding the origin of the Magorrian relation observed locally, where the mass of the stellar bulk in a galaxy appears to be tied to the mass of the underlying supermassive black hole. We exploit the combined use of far-infrared (IR) Herschel data and deep Chandra ˜160 ksec depth X-ray imaging of the COSMOS field to probe for AGN signatures in a large sample of >100 Dust-Obscured Galaxies (DOGs). Only a handful (˜20%) present individual X-ray detections pointing to the presence of significant AGN activity, while X-ray stacking analysis on the X-ray undetected DOGs points to a mix between AGN activity and star formation. Together, they are typically found on the main sequence of star-forming galaxies or below it, suggesting that they are either still undergoing significant build up of the stellar bulk or have started quenching. We find only ˜30% (6) Compton-thick AGN candidates (NH > 1024 cm–2), which is the same frequency found within other soft- and hard-X-ray selected AGN populations. This suggests that the large column densities responsible for the obscuration in Compton-thick AGNs must be nuclear and have little to do with the dust obscuration of the host galaxy. We find that DOGs identified to have an AGN share similar near-IR and mid-to-far-IR colors, independently of whether they are individually detected or not in the X-ray. The main difference between the X-ray detected and the X-ray undetected populations appears to be in their redshift distributions, with the X-ray undetected ones being typically found at larger distances. This strongly underlines the critical need for multiwavelength studies in order to obtain a more complete census of the obscured AGN population out to higher redshifts. For more details, we refer the reader to Riguccini et al. (2019).


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