Intra-night optical variability and radio characteristics of extremely radio-loud narrow-line Seyfert 1 galaxies
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866915404643827712 |
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| author | Singh, Veeresh Kumar, Parveen Das, Avik Kumar Ojha, Vineet |
| author_facet | Singh, Veeresh Kumar, Parveen Das, Avik Kumar Ojha, Vineet |
| contents | Narrow-line Seyfert 1 galaxies (NLS1s) are generally known to be radio-quiet Active Galactic Nuclei (AGN), but a tiny subset of them are found to be extremely radio-loud with radio loudness parameter ($R_{\rm 1.4~GHz}$) $>$ 100. Given their rarity we investigated intra-night optical variability (INOV) and radio characteristics of a sample of 16 extremely radio-loud NLS1s. For all but four sample sources we report intra-night photometric monitoring for the first time with at least one monitoring session per source lasting for a minimum of 3.0 hours duration. In our sample, we detect INOV with a high duty cycle (up to 25 per cent) and large average amplitude ($\overlineψ$ $\sim$ 0.16) similar to that found in blazars. Using 3.0 GHz Very Large Array Sky Survey (VLASS) and auxiliary multi-frequency radio data we find that our RL-NLS1s are luminous ($L_{\rm 3.0~GHz}$ $\geq$ 10$^{24}$ W~Hz$^{-1}$), compact (less than a few kpc), variable, flat spectrum ($α_{\rm radio}$ $>$ -0.5) radio sources. The INOV, radio characteristics, and radio luminosity ($L_{\rm 1.4~GHz}$) versus super-massive black hole mass ($M_{\rm SMBH}$) plot infer that extremely radio-loud NLS1s are low-$z$ and low-luminosity analogs of flat spectrum radio quasars wherein the former are powered by, on average, one order-of-magnitude less massive SMBHs. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_16486 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Intra-night optical variability and radio characteristics of extremely radio-loud narrow-line Seyfert 1 galaxies Singh, Veeresh Kumar, Parveen Das, Avik Kumar Ojha, Vineet Astrophysics of Galaxies High Energy Astrophysical Phenomena Narrow-line Seyfert 1 galaxies (NLS1s) are generally known to be radio-quiet Active Galactic Nuclei (AGN), but a tiny subset of them are found to be extremely radio-loud with radio loudness parameter ($R_{\rm 1.4~GHz}$) $>$ 100. Given their rarity we investigated intra-night optical variability (INOV) and radio characteristics of a sample of 16 extremely radio-loud NLS1s. For all but four sample sources we report intra-night photometric monitoring for the first time with at least one monitoring session per source lasting for a minimum of 3.0 hours duration. In our sample, we detect INOV with a high duty cycle (up to 25 per cent) and large average amplitude ($\overlineψ$ $\sim$ 0.16) similar to that found in blazars. Using 3.0 GHz Very Large Array Sky Survey (VLASS) and auxiliary multi-frequency radio data we find that our RL-NLS1s are luminous ($L_{\rm 3.0~GHz}$ $\geq$ 10$^{24}$ W~Hz$^{-1}$), compact (less than a few kpc), variable, flat spectrum ($α_{\rm radio}$ $>$ -0.5) radio sources. The INOV, radio characteristics, and radio luminosity ($L_{\rm 1.4~GHz}$) versus super-massive black hole mass ($M_{\rm SMBH}$) plot infer that extremely radio-loud NLS1s are low-$z$ and low-luminosity analogs of flat spectrum radio quasars wherein the former are powered by, on average, one order-of-magnitude less massive SMBHs. |
| title | Intra-night optical variability and radio characteristics of extremely radio-loud narrow-line Seyfert 1 galaxies |
| topic | Astrophysics of Galaxies High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2507.16486 |