Hubble's Galaxy NGC 4242 24 July 2017

Image: Hubble's galaxy NGC 4242 24 July 2017 as with much of the Universe, it is still a beautiful and ethereal sight. Provided by NASA Credit: ESA/Hubble & NASA Tucked away in the small northern constellation of Canes Venatici (The Hunting Dogs) is the galaxy NGC 4242, shown here as seen by the NASA/ESA Hubble Space Telescope. The galaxy lies some 30 million light-years from us. At this distance from Earth, actually not all that far on a cosmic scale, NGC 4242 is visible to anyone armed with even a basic telescope, as British astronomer William Herschel found when he discovered the galaxy in 1788. This image shows the galaxy's bright center and the surrounding dimmer and more diffuse "fuzz." Despite appearing to be relatively bright in this image, studies have found that NGC 4242 is actually relatively dim (it has a moderate-to-low surface brightness and low luminosity) and also supports a low rate of star formation. The galaxy also seems to have a weak bar of stars cutting through its asymmetric center, and a very faint and poorly-defined spiral structure throughout its disk. But if NGC 4242 is not all that remarkable, 1 / 2 APA citation: Image: Hubble's galaxy NGC 4242 (2017, July 24) retrieved 25 September 2021 from https://phys.org/news/2017-07-image-hubble-galaxy-ngc.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. 2 / 2 Powered by TCPDF (www.tcpdf.org).

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1. Introduction
THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 122:109È150, 1999 May ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. GALAXY STRUCTURAL PARAMETERS: STAR FORMATION RATE AND EVOLUTION WITH REDSHIFT M. TAKAMIYA1,2 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637; and Gemini 8 m Telescopes Project, 670 North Aohoku Place, Hilo, HI 96720 Received 1998 August 4; accepted 1998 December 21 ABSTRACT The evolution of the structure of galaxies as a function of redshift is investigated using two param- eters: the metric radius of the galaxy(Rg) and the power at high spatial frequencies in the disk of the galaxy (s). A direct comparison is made between nearby (z D 0) and distant(0.2 [ z [ 1) galaxies by following a Ðxed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broad- band images at D4500A observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between D3000 and D9000A (Williams et al.). The radius is measured from the intensity proÐle of the galaxy using the formulation of Petrosian, and it is argued to be a metric radius that should not depend very strongly on the angular resolution and limiting surface brightness level of the imaging data. It is found that the metric radii of nearby and distant galaxies are comparable to each other.
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Structure and Star Formation in Disk Galaxies I. Sample Selection And
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Classification of Galaxies Using Fractal Dimensions
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A Search For" Dwarf" Seyfert Nuclei. VII. a Catalog of Central Stellar
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Radial Star Formation Histories in Fifteen Nearby Galaxies
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SAC's 110 Best of the NGC
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A Multi-Wavelength Study of Star Formation in 15 Local Star-Forming Galaxies
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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/275963346 Enhancement Classiﬁcation of Galaxy Images Thesis · December 2014 DOI: 10.13140/RG.2.1.4152.4641 CITATIONS READS 0 493 1 author: John Jenkinson University of Texas at San Antonio 5 PUBLICATIONS 53 CITATIONS SEE PROFILE All content following this page was uploaded by John Jenkinson on 07 May 2015. The user has requested enhancement of the downloaded file. ENHANCEMENT CLASSIFICATION OF GALAXY IMAGES APPROVED BY SUPERVISING COMMITTEE: Arytom Grigoryan, Ph.D., Chair Walter Richardson, Ph.D. David Akopian, Ph.D. Accepted: Dean, Graduate School Copyright 2014 John Jenkinson All rights reserved. DEDICATION To my family. ENHANCEMENT CLASSIFICATION OF GALAXY IMAGES by JOHN JENKINSON, M.S. DISSERTATION Presented to the Graduate Faculty of The University of Texas at San Antonio In Partial Fulﬁllment Of the Requirements For the Degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING THE UNIVERSITY OF TEXAS AT SAN ANTONIO College of Engineering Department of Electrical and Computer Engineering December 2014 UMI Number: 1572687 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 1572687 Published by ProQuest LLC (2015). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC.
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A Composite H II Region Luminosity Function in Hα of Unprecedented Statistical Weight,
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