Download or read book A Study of the Neutral Hydrogen Content of Blue Compact Dwarf Galaxies written by Jeremy A MacHattie and published by . This book was released on 2013 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of a study of the neutral hydrogen (HI) content and distribution within a sample of 18 blue compact dwarf galaxies (BCDs) are presented. An investigation of the behaviour of the gas-to-dust ratio (GDR) as a function of metallicity (Z) is also presented. Observations of these BCDs was performed using the Very Large Array (VLA) in 2009, a year in which the array was undergoing a technological upgrade to the the Karl G. Jansky VLA (JVLA). The observations were reduced and images processed using the Astronomical Image Processing Software (AIPS), and data cubes for each galaxy were produced. The results include detections of eleven HI lines (two new detections) and ten background continuum sources (two new discoveries). All detections are at a higher resolution and/or sensitivity than previous measurements. These detections spanned a large range of line widths and HI masses; some masses comparable to those in normal galaxies. Of particular interest was the discovery of a compact absorption feature in the dwarf galaxy Haro 11. A paper submitted to the Monthly Notices of the Royal Astronomical Society (MNRAS) Letters on this discovery is presented. Another significant result was the discovery of a highly extended and massive HI region in the dwarf galaxy CGCG 297-017. For those galaxies with no detected HI line or radio continuum, an upper limit to the flux density was computed, which was used to derive upper limits to the HI mass or star-formation rate (SFR) respectively. Three HI flux density upper limits are new results, and seven continuum flux density upper limits are also new. The GDR-Z relation at low metallicities shows a potential power law or broken power law relation with a turning point at Z=7.96 or Z=8.05. To within error, these turning points and power law indices of the broken power law fits are consistent with other work.

Download or read book Neutral Hydrogen and Optical Studies of Dwarf Galaxies written by Jonathan Victor Smoker and published by . This book was released on 1993 with total page 2930 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Optical and Infrared Analysis of Blue Compact Dwarf Galaxies written by B. L. James and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An understanding of Blue Compact Dwarf galaxies (BCDs) and the processes occurring within their chemically un-evolved environments is fundamental in our understanding of the early universe. This thesis presents an investigation into their physical conditions, kinematics, chemical abundances and dust compositions. An optical integral field spectroscopy investigation of two perturbed BCDs, UM420 and UM462, is presented. Emission line maps show that both galaxies display signs of ongoing perturbation and/or interaction. Electron temperatures, densities and chemical abundances are computed from spectra integrated over the whole galaxies and for each area of star formation. A similar yet more complicated analysis is undertaken of the BCD Mrk996, which displays multi-component emission lines. The high excitation energy [O III] \lambda4363 and [N II] \lambda5755 lines are detected only in the inner regions and purely in broad component form, implying unusual excitation conditions. A separate physical analysis of the broad and narrow emission line regions is undertaken, yielding a revised metallicity and N/O ratio typical for the galaxy's metallicity. The mid-IR properties of 19 BCDs are studied through Spitzer spectral and imaging data. The depeletion of PAH emission in BCDs is investigated and found to be due to formation and destruction effects. The [S III] flux ratio is used as a density diagnostic, showing typically low-densities. Maps of PAH emission and radiation field hardness are derived from IRS spectral mapping data. Blackbody fits to IR photometric SEDs typically reveal two dust components. The observed physical and chemical properties of Mrk 996 are successfully reproduced using the photoionisation code MOCASSIN. The best-fit model involved the inclusion of a filling factor and an amorphous carbon dust component with a two-zone dust distribution. A STARBURST99 input spectrum was used, yielding ages consistent with the known young WR stars and old super star clusters within Mrk 996.

Download or read book The Minnesota Lectures on Extragalactic Neutral Hydrogen written by Evan David Skillman and published by . This book was released on 1996 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Optical and Infrared Analysis of Blue Compact Dwarf Galaxies written by Bethan Lesley James and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 1142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutral Hydrogen Observations of Binary Galaxies written by Gustaaf Adolf Van Moorsel and published by . This book was released on 1982 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Neutral Hydrogen Study of the Compact Galaxy II Zw 40 written by S. T. Gottesman and published by . This book was released on 1972 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interferometric observations at the 21 cm neutral hydrogen emission line have yielded information about the dynamics and structure of the compact galaxy II Zw 40. The neutral hydrogen follows a core-halo distribution with characteristic gaussian half-power widths of 52 arc sec and 350 arc sec. (Author).

Download or read book Abudance Analysis and Chemical Evolution of Blue Compact Dwarf Galaxies written by David Theodore Frayer and published by . This book was released on 1993 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutral Hydrogen Holes in the Dwarf Galaxy DDO 47 written by M. Anthony Wong and published by . This book was released on 1994 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Neutral Hydrogen Content of SO Galaxies written by Jo Ann Eder and published by . This book was released on 1982 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book FORMATION AND EVOLUTION OF BLUE COMPACT DWARF GALAXIES written by Luz Marina Cairós Barreto and published by . This book was released on 2001 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Neutral Hydrogen Study of Close and Wide Galaxy Pairs written by Tyler Eugene Nordgren and published by . This book was released on 1997 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Neutral Hydrogen Companions of Actively Star Forming Dwarf Galaxies written by Christopher Lee Taylor and published by . This book was released on 1995 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Interplay Among Black Holes Stars and ISM in Galactic Nuclei IAU S222 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2004 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: How massive are the largest and smallest nuclear black holes in galaxies? Why are the masses of nuclear black holes proportional to those of their host galaxy bulges? How is nuclear activity triggered? What are the observational signatures of such processes? What are the connections between the active nucleus, stars and interstellar medium in galaxies? Answers to these questions are addressed in this book, which presents a compilation of 191 works covering recent observations from X-rays to radio wavelengths, as well as theoretical modeling of accretion disks, stellar populations and galaxy and black hole evolution. This volume presents the nuclear activity as a phase in the life of a galaxy, which is intimately connected to the evolution of its stars and interstellar medium. It brings together recent developments in topics covering most aspects of galaxy evolution, and is a valuable resource for astronomers and graduate students working in extragalactic astronomy.

Download or read book On Formation and Evolution of the Blue Compact Dwarf Galaxies and on Star Formation Region Properties written by Yu. I. Izotov and published by . This book was released on 1989 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Star forming Dwarf Galaxies and Related Objects written by D. Kunth and published by Atlantica Séguier Frontières. This book was released on 1985 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: