Spectroscopically Identified Emission Line Galaxy Pairs in the WISP Survey

Y. Sophia Dai, Matthew M. Malkan, Harry I. Teplitz, Claudia Scarlata, Anahita Alavi, Hakim Atek, Micaela Bagley, Ivano Baronchelli, Andrew Battisti, Andrew J. Bunker, Nimish P. Hathi, Alaina Henry, Jiasheng Huang, Gaoxiang Jin, Zijian Li, Crystal Martin, Vihang Mehta, John Phillips, Marc Rafelski, Michael RutkowskiHai Xu, Cong K. Xu, Anita Zanella

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3 Scopus citations


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.

Original languageEnglish (US)
Article number156
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 20 2021

Bibliographical note

Funding Information:
Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. NASA ∣ GSFC ∣ Astrophysics Science Division (ASD) https://doi.org/10.13039/100007726 NAS 5-26555 NSFC ∣ Key Programme https://doi.org/10.13039/501100010903 10878003 NSFC 11933003 National Key R&D Program of China 2017YFA0402703 China manned space project CMS-CSST-2021-A05 ERC 789056 yes � 2021. The Author(s). Published by the American Astronomical Society. Creative Commons Attribution 4.0 licence

Publisher Copyright:
© 2021. The Author(s). Published by the American Astronomical Society.


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