J/ApJ/892/93 UV-NIR monitoring campaign of NGC 4395 (Cho+, 2020)
Variability and the size-luminosity relation of the intermediate-mass AGN
in NGC 4395.
Cho H., Woo J.-H., Hodges-kluck E., Son D., Shin J., Gallo E., Bae H.-J.,
Brink T.G., Cho W., Filippenko A.V., Horst J.C., Ilic D., Joner M.D.,
Kang D., Kang W., Kaspi S., Kim T., Kovacevic A.B., Kumar S., Le H.A.N.,
Nadzhip A.E., Pozo Nunez F., Metlov V.G., Oknyansky V.L., Park S.,
Popovic L.C., Rakshit S., Schramm M., Shatsky N.I., Spencer M., Sung E.-C.,
Sung H.-I., Tatarnikov A.M., Vince O.
<Astrophys. J., 892, 93-93 (2020)>
=2020ApJ...892...93C 2020ApJ...892...93C (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei; Photometry, ultraviolet; Photometry, H-alpha;
Photometry, infrared
Keywords: Reverberation mapping; Active galactic nuclei; Active galaxies
Galaxy nuclei; Low-luminosity active galactic nuclei
Intermediate-mass black holes; Seyfert galaxies
Abstract:
We present a variability study of the lowest-luminosity Seyfert 1
nucleus of the galaxy NGC 4395 based on photometric monitoring
campaigns in 2017 and 2018. Using 22 ground-based and space
telescopes, we monitored NGC 4395 with a ∼5-minute cadence during a
period of 10 days and obtained light curves in the ultraviolet (UV),
V, J, H, and K/Ks bands, as well as narrowband Hα. The rms
variability is ∼0.13mag in the Swift UVM2 and V filter light curves,
decreasing down to ∼0.01mag in the K filter. After correcting for the
continuum contribution to the Hα narrow band, we measured the
time lag of the Hα emission line with respect to the V-band
continuum as 55-31+27-122-67+33min in 2017 and
49-14+15-83-14+13min in 2018, depending on assumptions about
the continuum variability amplitude in the Hα narrow band. We
obtained no reliable measurements for the continuum-to-continuum lag
between UV and V bands and among near-IR bands, owing to the large
flux uncertainty of UV observations and the limited time baseline. We
determined the active galactic nucleus (AGN) monochromatic luminosity
at 5100Å, λLλ=(5.75±0.40)x1039erg/s, after
subtracting the contribution of the nuclear star cluster. While the
optical luminosity of NGC 4395 is two orders of magnitude lower than
that of other reverberation-mapped AGNs, NGC 4395 follows the
size-luminosity relation, albeit with an offset of 0.48dex
(≥2.5σ) from the previous best-fit relation of
Bentz+ 2013ApJ...767..149B 2013ApJ...767..149B
Description:
In 2017 and 2018 we performed intensive monitoring campaigns using
22 ground-based and one space-based telescope (Swift/UVOT) in order to
obtain well-sampled light curves of the AGN continuum flux and
Hα emission-line flux over a timescale of a few days. The
campaign was carried out from 2017 April 28 to May 5 and from 2018
April 6 to 9, during which we used various filters covering the UV to
the near-IR continuum. See Section 2.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
12 25 48.86 +33 32 48.7 NGC 4395 = UGC 7524
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 38 2212 Photometry Data
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See also:
III/116 : Spectrophotometric Standards (Massey+ 1988)
J/A+AS/131/1 : BVI photometry of 5 CVn cloud galaxies (Karachentsev+ 1998)
J/A+A/391/809 : HII regions in NGC 5457 and NGC 4395 (Cedres+, 2002)
J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004)
J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)
J/ApJ/632/799 : NGC4395 light curves (Peterson+, 2005)
J/ApJ/650/88 : NGC4395 light curves. III. (Desroches+, 2006)
J/ApJS/185/156 : The Lick AGN monitoring project (Walsh+, 2009)
J/ApJ/716/993 : LAMP: reverberation mapping of H and He lines (Bentz+, 2010)
J/ApJ/756/73 : gri LCs of the low-luminosity AGN NGC 4395 (Edri+, 2012)
J/ApJ/775/116 : z<0.06 active black hole galaxies from SDSS-DR8 (Reines+, 2013)
J/ApJ/825/126 : SEAMBHs. V. The third year (Du+, 2016)
J/ApJ/851/21 : SDSS RM project first year of observations (Grier+, 2017)
J/ApJ/856/6 : SEAMBHs IX. 10 new Hβ light curves (Du+, 2018)
J/ApJ/858/118 : Kinematic data of 3 nearby low-mass galaxies (Nguyen+, 2018)
J/ApJ/871/108 : Lick AGN monitoring project 2011: V band (Pancoast+, 2019)
J/ApJ/886/93 : SAMP. III. Opt. LCs and spectra of two AGNs (Rakshit+, 2019)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.5 d MJD Modified Julian Date of observation,
MJD-50000.0
12- 15 A4 -- Band Observation band (UVM2, V, Ha, J, H, K)
17- 21 F5.2 mag mag Apparent magnitude in Band
23- 27 F5.3 mag e_mag The 1σ uncertainty in mag
29- 38 A10 -- Tel Telescope identifier (1)
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Note (1): Telescope as follows:
BOAO = Bohyunsan Optical Astronomy Observatory 1.8m telescope
(194 occurrences);
CMO 2.5m = Caucasus Mountain Observatory 2.5m telescope (166 occurrences);
DOAO = Deokheung Optical Astronomy Observatory 1m telescope
(509 occurrences);
Hiroshima = Higashihiroshima Astronomical Observatory 1.5m telescope
(98 occurrences)
LOAO = Mt. Lemmon Optical Astronomy Observatory KASI 1m telescope
(280 occurrences);
MDM 1.3m = MDM Observatory 1.3m telescope (279 occurrences);
MDM 2.4m = MDM Observatory 2.4m telescope (307 occurrences);
MLO = Mt. Laguna Observatory 1m telescope (151 occurrences);
Nickel = Lick Observatory 1m telescope (105 occurrences);
Swift UVOT = UVOT instrument on Swift Ultraviolet/Optical Telescope
(72 occurrences);
WMO = West Mountain Observatory 0.91m telescope (51 occurrences).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Aug-2021