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Published December 20, 2021 | Accepted Version + Published
Journal Article Open

Spectroscopically Identified Emission Line Galaxy Pairs in the WISP Survey

Abstract

We identify a sample of spectroscopically measured emission line galaxy (ELG) Pairs up to z = 1.6 from the Wide Field Camera 3 (WFC3) Infrared Spectroscopic Parallels (WISP) survey. WISP obtained slitless, near-infrared grism spectroscopy along with direct imaging in the J and H bands by observing in the pure-parallel mode with the WFC3 on board the Hubble Space Telescope. From our search of 419 WISP fields covering an area of ∼0.5 deg², we find 413 ELG pair systems, mostly H_α emitters. We then derive reliable star formation rates (SFRs) based on the attenuation-corrected H_α fluxes. Compared to isolated galaxies, we find an average SFR enhancement of 40%–65%, which is stronger for major Pairs and Pairs with smaller velocity separations (Δ_v < 300 km s⁻¹). Based on the stacked spectra from various subsamples, we study the trends of emission line ratios in pairs, and find a general consistency with enhanced lower ionization lines. We study the pair fraction among ELGs, and find a marginally significant increase with redshift f ∝ (1 + z)^α, where the power-law index α = 0.58 ± 0.17 from z ∼ 0.2 to ∼1.6. The fraction of active galactic nuclei is found to be the same in the ELG Pairs as compared to the isolated ELGs.

Additional Information

© 2021. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 January 11; revised 2021 September 19; accepted 2021 October 11; published 2021 December 20. The authors would like to thank the referee for helpful suggestions. Y.S.D. thanks Andrea Faisst for helpful discussions. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11696, 12283, 12568, 12092, 13352, 13517, and 14178. Support for this work is also partly provided by the CASSACA and Chinese National Nature Science Foundation (NSFC) grant No. 10878003. Y.S.D. acknowledges the science research grants from NSFC grants 11933003, the National Key R&D Program of China via grant No. 2017YFA0402703, and the China Manned Space Project with No. CMS-CSST-2021-A05. A.J.B. acknowledges funding from the FirstGalaxies Advanced Grant from the European Research Council (ERC) under the European Union Horizon 2020 research and innovation program (grant agreement No. 789056). H.A. acknowledges support from CNES. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11696, 12283, 12568, 12092, 13352, 13517, and 14178.

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Published - Dai_2021_ApJ_923_156.pdf

Accepted Version - 2110.07316.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023