Bistatic Sounding of High-Latitude Ionospheric Irregularities Using a Decameter EKB Radar and an UTR-2 Radio Telescope: First Results

The first results of a new high resolution 21-cm HI line survey of M31 made with the Westerbork Synthesis Radio Telescope are presented. Five areas were mapped, covering the galaxy except for the extreme northern and southern parts, at a resolution of δα × δδ × δV = 24″ × 36″ × 3.2 km s−1. The spatial resolution corresponds to 30 × 120 pc at the distance of M31. This is of the same order as the resolution at the distance of the center or our own galaxy given by a 25-m dish. Consequently the M31 survey is comparable to surveys of the Milky Way galaxy in wealth of detail as well as in amount of data (∼ 1 Gigabyte).

Download Full-text

Measurement of Magnetic-Field Strengths in Molecular Clouds: Detection of OH Line Zeeman Splitting

Symposium - International Astronomical Union ◽

10.1017/s0074180900094821 ◽

1987 ◽

Vol 115 ◽

pp. 55-57

Author(s):

I. Kazès ◽

R. M. Crutcher ◽

T. H. Troland

Keyword(s):

Magnetic Field ◽

Radio Telescope ◽

Molecular Clouds ◽

Stokes Parameter ◽

Zeeman Splitting ◽

Spectral Lines ◽

First Results ◽

Extended Program ◽

Interstellar Molecular Clouds ◽

Field Strengths

We report here the first results of an extended program to measure magnetic-field strengths in interstellar molecular clouds. The very large radio telescope located near Nancay, France, has been used to measure the Stokes-parameter I and V spectra of the 1665 and 1667 MHz lines of OH in emission and in absorption from extended (non-masing) molecular clouds. Signals in the V spectra are produced by Zeeman splitting of the spectral lines; we derive magnetic-field strengths or limits from these data.

Download Full-text

Dynamics of the high-latitude ionospheric irregularities during the 17 March 2015 St. Patrick's Day storm: Ground-based GPS measurements

Space Weather ◽

10.1002/2015sw001237 ◽

2015 ◽

Vol 13 (9) ◽

pp. 585-597 ◽

Cited By ~ 53

Author(s):

Iurii Cherniak ◽

Irina Zakharenkova ◽

Robert J. Redmon

Keyword(s):

High Latitude ◽

Ionospheric Irregularities ◽

Gps Measurements

Download Full-text

Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318000704 ◽

2017 ◽

Vol 13 (S336) ◽

pp. 109-112

Author(s):

A. Tarchi ◽

P. Castangia ◽

G. Surcis ◽

A. Brunthaler ◽

K. M. Menten ◽

...

Keyword(s):

Radio Telescope ◽

Local Group ◽

Dwarf Galaxies ◽

Radio Continuum ◽

Maser Emission ◽

Star Forming ◽

Star Forming Regions ◽

First Results ◽

Ngc 6822 ◽

Almost All

AbstractThe dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

Download Full-text