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Redshifts of Emission-Line Objects in the Hubble Ultra Deep Field

Xu, Chun and Pirzkal, Norbert and Malhotra, Sangeeta and Rhoads, James E. and Mobasher, Bahram and Daddi, Emanuele and Gronwall, Caryl and Hathi, Nimish P. and Panagia, Nino and Ferguson, Henry C. and Koekemoer, Anton M. and Kümmel, Martin and Moustakas, Leonidas A. and Pasquali, Anna and di Serego Alighieri, Sperello and Vernet, Joel and Walsh, Jeremy R. and Windhorst, Rogier and Yan, Haojing (2007) Redshifts of Emission-Line Objects in the Hubble Ultra Deep Field. Astronomical Journal, 134 (1). pp. 169-178. ISSN 0004-6256.

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We present redshifts for 115 emission-line objects in the Hubble Ultra Deep Field identified through the Grism ACS Program for Extragalactic Science (GRAPES) project using the slitless grism spectroscopy mode of the Advanced Camera for Surveys on the Hubble Space Telescope (HST). The sample was selected by an emission-line search on all extracted one-dimensional GRAPES spectra. We identify the emission lines using line wavelength ratios where multiple lines are detected in the grism wavelength range (5800 Å ≲ λ ≲ 9600 Å), and using photometric redshift information where multiple lines are unavailable. We then derive redshifts using the identified lines. Our redshifts are accurate to δz ≈ 0.009, based on both statistical uncertainty estimates and comparison with published ground-based spectra. Over 40% of our sample is fainter than typical magnitude limits for ground-based spectroscopy (with i_(AB) > 25 mag). Such emission lines would likely remain undiscovered without our deep survey. The emission-line objects fall into three categories: (1) most are low- to moderate-redshift galaxies (0 ≤ z ≤ 2), including many actively star-forming galaxies with strong H II regions; (2) nine are high-redshift (4 ≤ z ≤ 7) Lyα emitters; and (3) at least three are candidate active galactic nuclei.

Item Type:Article
Related URLs:
URLURL TypeDescription
Pirzkal, Norbert0000-0003-3382-5941
Malhotra, Sangeeta0000-0002-9226-5350
Rhoads, James E.0000-0002-1501-454X
Daddi, Emanuele0000-0002-3331-9590
Hathi, Nimish P.0000-0001-6145-5090
Ferguson, Henry C.0000-0001-7113-2738
Koekemoer, Anton M.0000-0002-6610-2048
Moustakas, Leonidas A.0000-0003-3030-2360
di Serego Alighieri, Sperello0000-0001-8769-2692
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 1 (2007 July); received 2006 April 19; accepted for publication 2006 December 22; published 2007 May 17. This work was supported by grant GO-09793.01-A from the Space Telescope Science Institute, which is operated by Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. E. D. acknowledge support from NASA through the Spitzer Fellowship Program, under award 1268429. This project has made use of the aXe extraction software, produced by the Space Telescope European Coordinating Facility, Garching, Germany.We also made use of the mpfit IDL library, and we thank CraigMarkwardt for making this package public.
Funding AgencyGrant Number
NASA Spitzer Fellowship1268429
Subject Keywords:galaxies: formation; galaxies: high-redshift; galaxies: starburst
Issue or Number:1
Record Number:CaltechAUTHORS:20091117-121935886
Persistent URL:
Official Citation:Redshifts of Emission-Line Objects in the Hubble Ultra Deep Field Chun Xu, Norbert Pirzkal, Sangeeta Malhotra, James E. Rhoads, Bahram Mobasher, Emanuele Daddi, Caryl Gronwall, Nimish P. Hathi, Nino Panagia, Henry C. Ferguson, Anton M. Koekemoer, Martin Kümmel, Leonidas A. Moustakas, Anna Pasquali, Sperello di Serego Alighieri, Joel Vernet, Jeremy R. Walsh, Rogier Windhorst, and Haojing Yan 2007 The Astronomical Journal 134 169-178 doi: 10.1086/513512
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16732
Deposited By: Jason Perez
Deposited On:18 Nov 2009 21:48
Last Modified:09 Mar 2020 13:19

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