scholarly journals VLA observations of water maser emission associated with SVS 13

2002 ◽  
Vol 206 ◽  
pp. 59-62
Author(s):  
Luis F. Rodríguez ◽  
Guillem Anglada ◽  
José M. Torrelles ◽  
J. Eduardo Mendoza-Torres ◽  
Aubrey D. Haschick ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Radio Source ◽  
Angular Resolution ◽  
Radio Continuum ◽  
Large Array ◽  
Maser Emission ◽  
Very Large Array ◽  
Water Maser ◽  
East West ◽  
Made In

The young stellar object SVS 13 has been proposed as the powering source of the HH 7-11 objects. Recent observations have revealed that in the radio continuum (3.6-cm) the source is a binary separated by about 0.3 in the east-west direction. We present Very Large Array observations, made in the highest angular resolution A configuration, of H2O maser emission toward this source. Our data show that the H2O spots appear to be segregated in two velocity groups: a group with radial velocity similar to that of the ambient cloud (VLSR ⋍ 8 km s−1) that is associated with the western radio source, and a blueshifted (by ∼20 km s−1) velocity group that is associated with the eastern radio source. We discuss the possible implications of this observation.

scholarly journals A multifrequency study of the active star forming region NGC 6357

2006 ◽  
Vol 2 (S237) ◽  
pp. 400-400
Author(s):  
C. E. Cappa ◽  
R. H. Barbá ◽  
M. Arnal ◽  
N. Duronea ◽  
E. Fernández Lajús ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Massive Stars ◽  
Radio Continuum ◽  
Large Array ◽  
Schmidt Telescope ◽  
Ionized Gas ◽  
Very Large Array ◽  
Active Star ◽  
Star Forming ◽  
Spiral Arm

To investigate the interaction of the massive stars with the gas and dust in the active star forming region NGC 6357, located in the Sagittarius spiral arm at a distance of 1.7-2.6 kpc (Massey et al. 2001), we analyzed the distribution of the neutral and ionized gas, and that of the dust, based on Hα, [OIII] and [SII] images obtained with the Curtis-Schmidt telescope at CTIO, radio continuum observations at 1.465 MHz obtained with the Very Large Array (NRAO) in the DnC configuration (synthesized beam = 38″), Hi data from the Parkes survey (angular resolution = 15′), CO(1-0) observations obtained with the Nanten radiotelescope at Las Campanas Observatory (angular resolution = 2.7′), and IR images in the four MSX bands (angular resolution = 18.3″).

scholarly journals A Decade of Radio and X-ray Observations of SN 1993J

2005 ◽  
Vol 192 ◽  
pp. 3-11
Author(s):  
Schuyler D. Van Dyk ◽  
Kurt W. Weiler ◽  
Richard A. Sramek ◽  
Nino Panagia ◽  
Christopher Stockdale ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Continuum ◽  
Large Array ◽  
Very Large Array ◽  
X Ray ◽  
Radio Frequencies ◽  
Made In ◽  
Circumstellar Medium

SummaryWe review ten years of radio continuum and X-ray monitoring of the Type IIb SN 1993J in M81. The supernova (SN) has been observed continuously, since only a few days after explosion, by our group with the Very Large Array at a number of radio frequencies, as well as by other groups. As a result, it is among the best-studied radio supernovae. The observed synchrotron radio emission is thought to arise from the interaction of the SN shock with the pre-SN wind-established circumstellar medium around the progenitor star. We describe the properties of the circumstellar interaction, based on the more fully-developed dataset, and compare this to our earlier characterization made in 1994. SN 1993J has also been a target of X-ray satellites, and we briefly discuss the nature of the X-ray emission and, together with the radio emission, describe the implications for the nature of the SN’s progenitor.

scholarly journals Imaging the water masers toward the H2O-PN IRAS 18061–2505

2012 ◽  
Vol 8 (S287) ◽  
pp. 258-259
Author(s):  
Yolanda Gómez ◽  
Daniel Tafoya ◽  
Olga Suárez ◽  
Jose F. Gómez ◽  
Luis F. Miranda ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Central Star ◽  
Large Array ◽  
Maser Emission ◽  
Very Large Array ◽  
Kinematical Model ◽  
Water Masers ◽  
Central Stars ◽  
Water Maser

AbstractIt has been suggested that the presence of disks or tori around the central stars of pre Planetary Nebulae and Planetary Nebulae is related to the collimation of the jet that are frequently observed in these sources. These disks or tori can be traced by the maser emission of some molecules such as water. In this work we present Very Large Array (VLA) observations of the water maser emission at 22 GHz toward the PN IRAS 18061–2505, for which the masers appear located on one side of the central star. For comparison with the observations, we present a simple kinematical model of a disk rotating and expanding around the central star. The model matches qualitatively the observations. However, since the masers appear only on one side of the disk, these results are not conclusive.

scholarly journals Submillimeter Array observations of 321 GHz water maser emission in Cepheus A

2007 ◽  
Vol 3 (S242) ◽  
pp. 489-493
Author(s):  
Nimesh A. Patel ◽  
Salvador Curiel ◽  
Qizhou Zhang ◽  
T. K. Sridharan ◽  
Paul T. P. Ho ◽  
...  
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Large Array ◽  
Maser Emission ◽  
Very Large Array ◽  
Star Forming ◽  
Water Masers ◽  
Cepheus A ◽  
First Time ◽  
Water Maser

AbstractUsing the Submillimeter Array (SMA) we have imaged for the first time the 321.226 GHz, 1029 − 936 ortho-H2O maser emission. This is also the first detection of this line in the Cepheus A high-mass star-forming region. The 22.235 GHz, 616 – 523 water masers were also observed with the Very Large Array 43 days following the SMA observations. Three of the nine detected submillimeter maser spots are associated with the centimeter masers spatially as well as kinematically, while there are 36 22 GHz maser spots without corresponding submillimeter masers. In the HW2 source, both the 321 GHz and 22 GHz masers occur within the region of ~1″ which includes the disk-jet system, but the position angles of the roughly linear structures traced by the masers indicate that the 321 GHz masers are along the jet while the 22 GHz masers are perpendicular to it. We interpret the submillimeter masers in Cepheus A to be tracing significantly hotter regions (600~2000 K) than the centimeter masers.

scholarly journals Maser emission towards the young planetary nebula IRAS 17347-3139

2007 ◽  
Vol 3 (S242) ◽  
pp. 334-335
Author(s):  
D. Tafoya ◽  
Y. Gómez ◽  
J. F. Gómez ◽  
I. de Gregorio-Monsalvo ◽  
L. Uscanga ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Angular Resolution ◽  
Radio Continuum ◽  
Maser Emission ◽  
Closed Ring ◽  
First Time ◽  
Water Maser

AbstractWe have re-analyzed observations of the water maser emission in IRAS 17347-3139 carried out previously and compared them with new higher angular resolution and more sensitive radio-continuum observations to explain the shift between the position of the peak of the radio-continuum with respect to the center of the ring-like distribution. From our analysis, we found that the water maser emission is not distributed in a closed ring-like structure, but in what appears to be a segment of an ellipse centered in the position of the peak of the radio-continuum. These results can explain the shift between the radio-continuum and the water maser emission. We also present interferometric observations of the OH maser emission towards IRAS 17347-3139 from which we have found that the OH maser emission detected previously is not associated with this source. Furthermore, since our observations are more sensitive, we have detected for the first time weak OH maser emission associated with IRAS 17347-3139.

scholarly journals 20cm VLA radio-continuum study of M31: Images and point source catalogues

2012 ◽  
pp. 41-68 ◽  
Author(s):  
T.J. Galvin ◽  
M.D. Filipovic ◽  
E.J. Crawford ◽  
N.F.H. Tothill ◽  
G.F. Wong ◽  
...  
Keyword(s):  
High Resolution ◽  
Angular Resolution ◽  
High Sensitivity ◽  
Radio Continuum ◽  
High Angular Resolution ◽  
Radio Sources ◽  
Large Array ◽  
Complete Sample ◽  
Very Large Array ◽  
Discrete Radio Sources

We present a series of new high-sensitivity and high-resolution radio-continuum images of M31 at ?=20 cm (?=1.4 GHz). These new images were produced by merging archived 20 cm radio-continuum observations from the Very Large Array (VLA) telescope. Images presented here are sensitive to rms=60 ?Jy and feature high angular resolution (<10??). A complete sample of discrete radio sources have been catalogued and analyzed across 17 individual VLA projects. We identified a total of 864 unique discrete radio sources across the field of M31. One of the most prominent regions in M31 is the ring feature for which we estimated total integrated flux of 706 mJy at ?=20 cm. We compare here detected sources to those listed in Gelfand et al. (2004) at ?=92 cm and find 118 sources in common to both surveys. The majority (61%) of these sources exhibit a spectral index of ? <-0.6 indicating that their emission is predominantly non-thermal in nature, that is more typical for background objects.

Bipolar outflow of gas in the spiral galaxy NGC 3079

1986 ◽  
Vol 64 (4) ◽  
pp. 531-535 ◽  
Author(s):  
Nebojsa Duric ◽  
E. R. Seaquist
Keyword(s):  
Spectral Index ◽  
Spiral Galaxy ◽  
Central Region ◽  
Qualitative Description ◽  
Radio Continuum ◽  
Large Array ◽  
Very Large Array ◽  
Bipolar Outflow ◽  
The Galaxy

Very large array, radio-continuum observations of the edge-on spiral galaxy NGC 3079 are presented. The observations reveal that the nucleus has windlike properties and that the central region of the galaxy exhibits an unusual figure-eight morphology that shows evidence of severe depolarization and a flattening spectral index away from the nucleus. A qualitative description of a model is presented to account for the observed radio properties. It is shown that a wind-driven shock propagating away from the nucleus and focused by the ambient disk gas can give rise to the observed morphology.

scholarly journals Class I methanol masers in the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 147-149
Author(s):  
L. O. Sjouwerman ◽  
Y. M. Pihlström
Keyword(s):  
Galactic Center ◽  
Class I ◽  
Large Array ◽  
Maser Emission ◽  
Very Large Array ◽  
Sagittarius A ◽  
Current Location ◽  
Theoretical Predictions ◽  
Methanol Masers ◽  
Sgr A

AbstractWe report on the detection of 36 and 44 GHz Class I methanol (CH3OH) maser emission in the Sagittarius A (Sgr A) complex with the Karl G. Jansky Very Large Array (VLA). These VLA observations show that the Sgr A complex harbors at least three different maser tracers of shocked regions in the radio regime. The 44 GHz masers correlate with the positions and velocities of previously detected 36 GHz CH3OH masers, but less with 1720 MHz OH masers. Our detections agree with theoretical predictions that the densities and temperatures conducive for 1720 MHz OH masers may also produce 36 and 44 GHz CH3OH maser emission. However, many 44 GHz masers do not overlap with 36 GHz methanol masers, suggesting that 44 GHz masers also arise in regions too hot and too dense for 36 GHz masers to form. This agrees with the non-detection of 1720 MHz OH masers in the same area, which are thought to be excited under even cooler and less dense conditions. We speculate that the geometry of the 36 GHz masers outlines the current location of a shock front.

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