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We present the first INTEGRAL observations of the type 1.5 Seyfert galaxy NGC 4151. Combining several INTEGRAL observations performed during 2003, totaling about 400 ks of exposure time, allows us to study the spectrum in the 2 - 300 keV…

We study the physical and chemical properties of a sample of HII regions located at RG >11 kpc and present the radial distribution of abundances towards the Galaxy anticentre. We carried out optical spectroscopic observations of nine HII…

Astrophysics of Galaxies · Physics 2017-01-18 Alba Fernández-Martín , Enrique Pérez-Montero , José Manuel Vílchez , Antonio Mampaso

HII regions made of gas ionized by radiations from young massive stars, are widely distributed in the Milky Way. They are tracers for star formation, and their distributions are correlated with the Galactic spiral structure. Radio…

Astrophysics of Galaxies · Physics 2021-11-03 Chuan-Peng Zhang , Jin-Long Xu , Guang-Xing Li , Li-Gang Hou , Nai-Ping Yu , Peng Jiang

The Galactic Center lobe is a degree-tall shell seen in radio continuum images of the Galactic center (GC) region. If it is actually located in the GC region, formation models would require massive energy input (e.g., starburst or jet) to…

Astrophysics of Galaxies · Physics 2011-02-11 C. J. Law , D. Backer , F. Yusef-Zadeh , R. Maddalena

We present sub-arcminute resolution imaging of the Galactic supernova remnant W49B at 74 MHz (25") and 327 MHz (6"), the former being the lowest frequency at which the source has been resolved. While the 327 MHz image shows a shell-like…

Astrophysics · Physics 2009-11-06 C. K. Lacey , T. Joseph W. Lazio , Namir E. Kassim , N. Duric , D. S. Briggs , K. K. Dyer

We discuss the first results from our mid-infrared imaging survey of Milky Way Giant HII regions with our detailed analysis of W51A, which is one of the largest GHII regions in our Galaxy. We used the FORCAST instrument on SOFIA to obtain…

Astrophysics of Galaxies · Physics 2019-03-27 Wanggi Lim , James M. De Buizer

We present maps of the 22MHz radio emission between declinations -28d and +80d, covering ~73% of the sky, derived from observations with the 22MHz radiotelescope at the Dominion Radio Astrophysical Observatory (DRAO). The resolution of the…

Astrophysics · Physics 2009-10-31 R. S. Roger , C. H. Costain , T. L. Landecker , C. M. Swerdlyk

We derive the radio spectral index of the Barnard Loop (BL) from large-scale radio surveys at four frequencies and find it to be a thermal source. We use the radio data together with H-alpha data to determine the electron temperature in BL,…

Astrophysics · Physics 2009-10-31 Carl Heiles , L. M. Haffner , R. J. Reynolds , S. L. Tufte

We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of…

Astrophysics of Galaxies · Physics 2015-05-18 M. R. Samal , A. K. Pandey , D. K. Ojha , S. K. Ghosh , V. K. Kulkarni , N. Kusakabe , M. Tamura , B. C. Bhatt , M. A. Thompson , R. Sagar

We have observed the compact HII region complex nearest to the dynamical center of the Galaxy, G-0.02-0.07, using ALMA in the H42a recombination line, CS J=2-1, H13CO+ J=1-0, and SiO v=0, J=2-1 emission lines, and 86 GHz continuum emission.…

We investigate the electron temperature gradient in the galactic disk as measured by young HII regions on the basis of radio recombination lines and the corresponding gradient in planetary nebulae (PN) based on [OIII] electron temperatures.…

Astrophysics · Physics 2015-06-24 W. J. Maciel , C. Quireza , R. D. D. Costa

We present results of high-resolution radio continuum observations towards the binary star WR 21a (Wack 2134) obtained with the Australia Telescope Compact Array (ATCA) at 4.8 and 8.64 GHz. We detected the system at 4.8 GHz (6 cm) with a…

Astrophysics · Physics 2016-08-30 Paula Benaglia , Gustavo E. Romero , Baerbel Koribalski , A. M. T. Pollock

Elemental abundance patterns in the Galactic disk constrain theories of the formation and evolution of the Milky Way. HII region abundances are the result of billions of years of chemical evolution. We made radio recombination line and…

Astrophysics of Galaxies · Physics 2015-05-18 Dana S. Balser , Trey V. Wenger , L. D. Anderson , T. M. Bania

Integral field spectroscopy (IFS) is presented for star forming regions in M33. A central area of 300 x 500 pc^2 and the external HII region IC 132, at a galactocentric distance {\sim} 19arcmin (4.69 kpc) were observed with the Potsdam…

At low radio frequencies (< 100 MHz), classical HII regions may become optically thick (optical depth > 1) and can be observed as discrete absorption regions against the Galactic nonthermal background emission created by Galactic cosmic ray…

Astrophysics · Physics 2008-11-26 Michael E. Nord , P. A. Henning , R. J. Rand , T. Joseph W. Lazio , Namir E. Kassim

The relation between parameters the D/sqrt(I) and Ic/Isum and radiation patterns of the optical and radio components of an extended radio source is analyzed, where D and I are the apparent size and observed radiation intensity of the source…

Astrophysics of Galaxies · Physics 2016-12-21 V. R. Amirkhanyan

We report Giant Meterwave Radio Telescope (GMRT) continuum observations of six nearby normal galaxies at 333 MHz. The galaxies are observed with angular resolutions better than ~20" (corresponding to a linear scale of about 0.4 - 1 kpc).…

Astrophysics of Galaxies · Physics 2015-05-30 Aritra Basu , Dipanjan Mitra , Yogesh Wadadekar , C. H. Ishwara-Chandra

Observations at mid-infrared (4.8-17.65 um) and radio (0.7-1.3 cm) wavelengths are used to constrain the structure of the high-mass star-forming region W3 IRS5 on 0.1'' (200 AU) scales. Two bright mid-infrared sources are detected, as well…

Astrophysics · Physics 2009-11-10 F. F. S. van der Tak , P. G. Tuthill , W. C. Danchi

We present new multi-frequency radio continuum imaging of the dwarf starburst galaxy NGC 625 obtained with the Very Large Array. Data at 20, 6, and 3.6 cm reveal global continuum emission dominated by free-free emission, with only mild…

Astrophysics · Physics 2009-11-10 John M. Cannon , Evan D. Skillman

A series of new radio-continuum ({\lambda}=20, 13, 6 and 3 cm) mosaic images focused on the NGC55 galactic system were produced using archived observational data from the Australia Telescope Compact Array. These new images are both very…