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Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring

Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring
Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring
The time delay between flux variations in different wavelength bands can be used to probe the inner regions of active galactic nuclei (AGN). Here, we present the first measurements of the time delay between optical and near-infrared (NIR) flux variations in H0507+164, a nearby Seyfert 1.5 galaxy at z = 0.018. The observations in the optical V -band and NIR J, H and Ks bands carried over 35 epochs during the period October 2016 to April 2017 were used to estimate the inner radius of the dusty torus. From a careful reduction and analysis of the data using cross-correlation techniques, we found delayed responses of the J, H and Ks light curves to the V -band light curve. In the rest frame of the source, the lags between optical and NIR bands are found to be $27.1^{+13.5}_{-12.0}$ days (V vs. J), $30.4^{+13.9}_{-12.0}$ days (V vs. H) and $34.6^{+12.1}_{-9.6}$ days (V vs. K ). The lags between the optical and different NIR bands are thus consistent with each other. The measured lags indicate that the inner edge of dust torus is located at a distance of 0.029 pc from the central UV/optical AGN continuum. This is larger than the radius of the broad line region of this object determined from spectroscopic monitoring observations thereby supporting the unification model of AGN. The location of H0507+164 in the {\tau} - MV plane indicates that our results are in excellent agreement with the now known lag-luminosity scaling relationship for dust in AGN.
astro-ph.GA
1365-2966
Mandal, Amit Kumar
04a4cf91-b924-42a5-842b-7f177f91b922
Rakshit, Suvendu
6bd5cf6c-ff47-48ab-89fe-68113476ae26
Kurian, Kshama S.
3b7c577b-704a-4fdc-a7e0-08601ffd1f5d
Stalin, C. S.
889816b3-bc9a-491a-adb6-c4ba2fe0438b
Mathew, Blesson
d4998c72-ae76-4058-81aa-f47f685edbc7
Hoenig, Sebastian
be0bb8bc-bdac-4442-8edc-f735834f3917
Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9
Sagar, Ram
8cd09c28-5d56-499b-b0e3-7e176d9ae2cc
Pandge, M. B.
47bc7464-6563-41c6-ae04-e4c1fc53be21
Mandal, Amit Kumar
04a4cf91-b924-42a5-842b-7f177f91b922
Rakshit, Suvendu
6bd5cf6c-ff47-48ab-89fe-68113476ae26
Kurian, Kshama S.
3b7c577b-704a-4fdc-a7e0-08601ffd1f5d
Stalin, C. S.
889816b3-bc9a-491a-adb6-c4ba2fe0438b
Mathew, Blesson
d4998c72-ae76-4058-81aa-f47f685edbc7
Hoenig, Sebastian
be0bb8bc-bdac-4442-8edc-f735834f3917
Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9
Sagar, Ram
8cd09c28-5d56-499b-b0e3-7e176d9ae2cc
Pandge, M. B.
47bc7464-6563-41c6-ae04-e4c1fc53be21

Mandal, Amit Kumar, Rakshit, Suvendu, Kurian, Kshama S., Stalin, C. S., Mathew, Blesson, Hoenig, Sebastian, Gandhi, Poshak, Sagar, Ram and Pandge, M. B. (2018) Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring. Monthly Notices of the Royal Astronomical Society. (doi:10.1093/mnras/sty200).

Record type: Article

Abstract

The time delay between flux variations in different wavelength bands can be used to probe the inner regions of active galactic nuclei (AGN). Here, we present the first measurements of the time delay between optical and near-infrared (NIR) flux variations in H0507+164, a nearby Seyfert 1.5 galaxy at z = 0.018. The observations in the optical V -band and NIR J, H and Ks bands carried over 35 epochs during the period October 2016 to April 2017 were used to estimate the inner radius of the dusty torus. From a careful reduction and analysis of the data using cross-correlation techniques, we found delayed responses of the J, H and Ks light curves to the V -band light curve. In the rest frame of the source, the lags between optical and NIR bands are found to be $27.1^{+13.5}_{-12.0}$ days (V vs. J), $30.4^{+13.9}_{-12.0}$ days (V vs. H) and $34.6^{+12.1}_{-9.6}$ days (V vs. K ). The lags between the optical and different NIR bands are thus consistent with each other. The measured lags indicate that the inner edge of dust torus is located at a distance of 0.029 pc from the central UV/optical AGN continuum. This is larger than the radius of the broad line region of this object determined from spectroscopic monitoring observations thereby supporting the unification model of AGN. The location of H0507+164 in the {\tau} - MV plane indicates that our results are in excellent agreement with the now known lag-luminosity scaling relationship for dust in AGN.

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sty200 - Accepted Manuscript
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Accepted/In Press date: 22 January 2018
e-pub ahead of print date: 29 January 2018
Additional Information: 8 pages, 4 figures, accepted by MNRAS main journal
Keywords: astro-ph.GA

Identifiers

Local EPrints ID: 417645
URI: http://eprints.soton.ac.uk/id/eprint/417645
ISSN: 1365-2966
PURE UUID: d7a7205f-fd0a-487f-bd58-3629a0e956e1
ORCID for Poshak Gandhi: ORCID iD orcid.org/0000-0003-3105-2615

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Date deposited: 08 Feb 2018 17:30
Last modified: 16 Mar 2024 04:20

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Contributors

Author: Amit Kumar Mandal
Author: Suvendu Rakshit
Author: Kshama S. Kurian
Author: C. S. Stalin
Author: Blesson Mathew
Author: Poshak Gandhi ORCID iD
Author: Ram Sagar
Author: M. B. Pandge

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