A Multi-wavelength Study of the Dual Nuclei in Mrk 212
| Autor: | M. Honey, Mousumi Das, S. Vaddi, Preeti Kharb, P. T. Rahna, K. Rubinur, A. Paswan, Jayant Murthy |
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| Rok vydání: | 2020 |
| Předmět: |
Active galactic nucleus
Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics medicine.disease_cause 01 natural sciences law.invention Jansky Telescope Radio telescope law 0103 physical sciences medicine 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Physics Spectral index 010308 nuclear & particles physics Star formation Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Galaxy Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Ultraviolet |
| DOI: | 10.48550/arxiv.2010.14914 |
| Popis: | We present radio observations of the galaxy merger remnant Mrk 212 with the Karl G. Jansky Very Large Array (VLA) and the upgraded Giant Meter Radio Telescope (uGMRT). Mrk 212 has two previously known radio sources associated with the two optical nuclei, S1 and S2, with a projected separation of ~6 kpc, making it a dual active galactic nuclei (AGN) candidate. Our new 15 GHz VLA observations reveal that S1 is a double radio source centred around the optical nucleus; its total extent is ~750 parsec and its average 1.4-8.5 GHz spectral index is -0.81 +/- 0.06. S1 therefore, resembles a compact symmetric object (CSO). The 15 GHz VLA image identifies the radio source at S2 to be a compact core. Our radio observations therefore strongly support the presence of a dual AGN in Mrk 212. The optical emission line flux ratios obtained from the Himalayan Chandra Telescope (HCT) observations however, show that S1 and S2 both fall in the AGN + SF (star formation) region of the BPT diagram. Weak AGN lying in the SF or AGN + SF intermediate regions in the BPT diagram have indeed been reported in the literature; our sources clearly fall in the same category. We find an extended radio structure in our newly reduced 8.5 GHz VLA data, that is offset by ~1" from the optical nucleus S2. New deep FUV and NUV observations with the Ultraviolet Imaging Telescope (UVIT) aboard AstroSat reveal SF knots around S2 as well as kpc-scale tidal tails; the SF knots around S2 coincide with the extended radio structure detected at 8.5 GHz. The radio spectral indices are consistent with SF. Any possible association with the AGN in S2 is unclear at this stage. Comment: 14 pages, 7 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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