We identify a sample of spectroscopically measured emission line galaxy (ELG) pairs up to z=1.6 from the 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 Wide Field Camera Three (WFC3) on the Hubble Space Telescope (HST). From our search of 419 WISP fields covering an area of ~0.5 deg2, we find 413 ELG pair systems, mostly Halpha emitters. We then derive reliable star formation rates (SFRs) based on the attenuation-corrected Halpha 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 (Delta_v < 300 km/s). 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 \alpha=0.58±0.17 from z∼0.2 to z∼1.6. The fraction of Active galactic Nuclei (AGNs), is found to be the same in the ELG pairs as compared to isolated ELGs.
@article{arxiv.2110.07316,
title = {Spectroscopically Identified Emission Line Galaxy Pairs in the WISP survey},
author = {Y. Sophia Dai and Matthew M. Malkan and Harry I. Teplitz and Claudia Scarlata and Anahita Alavi and Hakim Atek and Micaela Bagley and Ivano Baronchelli and Andrew Battisti and Andrew J Bunker and Nimish P. Hathi and Alaina Henry and Jiasheng Huang and Gaoxiang Jin and Zijian Li and Crystal Martin and Vihang Mehta and John Phillips and Marc Rafelski and Michael Rutkowski and Hai Xu and Cong K Xu and Anita Zanella},
journal= {arXiv preprint arXiv:2110.07316},
year = {2022}
}
Comments
22 pages, 9 figures, 6 tables, accepted for publication in ApJ