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On the Origin of Lopsidedness in Galaxies as Determined from the Spitzer Survey of Stellar Structure in Galaxies (S^4G)

Zaritsky, Dennis and Laine, Seppo and Mizusawa, Trisha (2013) On the Origin of Lopsidedness in Galaxies as Determined from the Spitzer Survey of Stellar Structure in Galaxies (S^4G). Astrophysical Journal, 772 (2). Art. No. 135. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20130829-101201167

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Abstract

We study the m = 1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f *, within one radial scale length, and (4) correlates directly with f * measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness (<A_1>_i + <A_1>_o)/2 < 0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0004-637X/772/2/135 DOIArticle
http://arxiv.org/abs/1305.2940arXivDiscussion Paper
ORCID:
AuthorORCID
Zaritsky, Dennis0000-0002-5177-727X
Laine, Seppo0000-0003-1250-8314
Mizusawa, Trisha0000-0001-7182-5307
Additional Information:© 2013 The American Astronomical Society. Received 2013 February 10; accepted 2013 May 13; published 2013 July 17. D.Z. acknowledges financial support from NASA ADAP NNX12AE27G and thanks the Max Planck Institute for Astronomy and NYU CCPP for their hospitality during long-term visits. E.A. and A.B. acknowledge the CNES (Centre National d’Etudes Spatiales—France) for financial support. We acknowledge the support from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement PITN-GA-2011-289313. The authors thank the entire S^4G team for the efforts in making this program possible. This research has made use of the NASA/ IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This research is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Taehyun Kim is a student at the National Radio Astronomy Observatory.
Funders:
Funding AgencyGrant Number
NASANNX12AE27G
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Marie Curie FellowshipPITN-GA-2011-289313
Subject Keywords:galaxies: fundamental parameters – galaxies: kinematics and dynamics – galaxies: structure
Issue or Number:2
Record Number:CaltechAUTHORS:20130829-101201167
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130829-101201167
Official Citation:On the Origin of Lopsidedness in Galaxies as Determined from the Spitzer Survey of Stellar Structure in Galaxies (S4G) Dennis Zaritsky et al. 2013 ApJ 772 135
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:40990
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:30 Aug 2013 18:55
Last Modified:13 Nov 2019 23:32

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