J/ApJ/947/2 AGN STORM 2. III. A NICER view of Mrk 817 (Partington+, 2023)
AGN STORM 2.
III. A NICER view of the variable X-ray obscurer in Mrk 817.
Partington E.R., Cackett E.M., Kara E., Kriss G.A., Barth A.J.,
De Rosa G., Homayouni Y., Horne K., Landt H., Zoghbi A., Edelson R.,
Arav N., Boizelle B.D., Bentz M.C., Brotherton M.S., Byun D.,
Dalla Bonta E., Dehghanian M., Du Pu, Fian C., Filippenko A.V.,
Gelbord J., Goad M.R., Gonzalez Buitrago D.H., Grier C.J., Hall P.B.,
Hu C., Ilic D., Joner M.D., Kaspi S., Kochanek C.S., Korista K.T.,
Kovacevic A.B., Kynoch D., McLane J.N., Mehdipour M., Miller J.A.,
Panagiotou C., Plesha R., Popovic L. C, Proga D., Rogantini D.,
Storchi-Bergmann T., Sanmartim D., Siebert M.R., Vestergaard M.,
Ward M.J., Waters T., Zaidouni F.
<Astrophys. J., 947, 2 (2023)>
=2023ApJ...947....2P 2023ApJ...947....2P
ADC_Keywords: Galaxies, Seyfert; Active gal. nuclei; X-ray sources
Keywords: Accretion ; X-ray active galactic nuclei ; Black hole physics ;
Active galactic nuclei
Abstract:
The AGN STORM 2 Collaboration targeted the Seyfert 1 galaxy Mrk 817
for a year-long multiwavelength, coordinated reverberation mapping
campaign including Hubble Space Telescope, Swift, XMM-Newton, NICER,
and ground-based observatories. Early observations with NICER and XMM
revealed an X-ray state 10 times fainter than historical observations,
consistent with the presence of a new dust-free, ionized obscurer. The
following analysis of NICER spectra attributes variability in the
observed X-ray flux to changes in both the column density of the
obscurer by at least one order of magnitude (NH ranges from
2.85-0.33+0.48x1022cm-2 to 25.6-3.5+3.0x1022cm-2) and
the intrinsic continuum brightness (the unobscured flux ranges from
10-11.8 to 10-10.5erg/s/cm-2). While the X-ray flux generally
remains in a faint state, there is one large flare during which Mrk817
returns to its historical mean flux. The obscuring gas is still
present at lower column density during the flare, but it also becomes
highly ionized, increasing its transparency. Correlation between the
column density of the X-ray obscurer and the strength of UV broad
absorption lines suggests that the X-ray and UV continua are both
affected by the same obscuration, consistent with a clumpy disk wind
launched from the inner broad-line region.
Description:
NICER monitoring of Mrk 817 began on 2020 November 28 (Day 9181),
with an approximate cadence of 2 days as part of a TOO request
(PI: E. Cackett, Target ID: 320186), and continued with observations
from GO proposal 4128. We excluded observations with a total exposure
time of <400s, leaving 183 epochs.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
14 36 22.08 +58 47 39.3 Mrk 817 = LEDA 52202
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 28 138 NICER count rate and hardness
table3.dat 125 138 Spectral analysis results: observation date and
spectral parameters fit using the methods in
Section 3.1
table4.dat 55 192 NICER source and background count rate for each
estimator during the period of continuous Swift
monitoring
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See also:
J/ApJ/613/682 : AGN central masses & broad-line regions (Peterson+, 2004)
J/ApJ/641/L21 : BH mass and velocity dispersion relation (Greene+, 2006)
J/ApJ/660/1072 : Unified model of active galactic nuclei (Wang+, 2007)
J/other/ChA+A/32.351 : Accretion rate distributions of AGNs (Bao+, 2008)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/ApJ/697/182 : Dust emission from unobscured AGN (Thompson+, 2009)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJ/739/57 : Ultra hard X-ray AGNs in the Swift/BAT survey (Koss+, 2011)
J/MNRAS/414/500 : Spitzer/IRS ATLAS project source (Hernan-Caballero+, 2011)
J/ApJS/199/8 : Interstellar column density compilation (Gudennavar+, 2012)
J/ApJ/753/L2 : Reverberation mapping of AGNs (Assef+, 2012)
J/ApJ/761/184 : IR luminosities for dusty AGNs and QSOs (Weedman+, 2012)
J/ApJ/788/159 : 17 Seyfert 1 galaxies light curves (Koshida+, 2014)
J/ApJS/216/17 : AKARI 2.5-5um spectra of nearby Type-1 AGNs (Kim+, 2015)
J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)
J/ApJ/813/82 : z<0.06 broad-line AGN emission-line measures (Reines+, 2015)
J/A+A/588/A70 : Hard X-ray view of the soft excess in AGN (Boissay+, 2016)
J/ApJ/818/L14 : RM AGNs accretion rates and BH masses (Du+, 2016)
J/ApJ/831/134 : BH masses & host gal. dispersion vel. (van den Bosch, 2016)
J/ApJ/870/123 : Swift optical & UV flux of four AGNs (Edelson+, 2019)
J/ApJ/877/23 : SEAMBHs. X. RM campaign compilation (Lu+, 2019)
J/ApJ/886/42 : Reverberation mapping & opt. spectra of AGNs (Du+, 2019)
J/A+A/625/A122 : CIELO-RGS, soft X-ray ionized emission lines (Mao+, 2019)
J/MNRAS/489/3351 : Spectral energy distributions of AGNs (Brown+, 2019)
J/MNRAS/494/5793 : IR photometry and SEDs of hard X-ray AGNs (Kilerci+, 2020)
J/ApJ/892/18 : X-ray & MIR luminosities of the GBT galaxies (Kuo+, 2020)
J/ApJ/897/111 : Compilation of BH, bulge and stellar masses (Zaw+, 2020)
J/ApJ/899/82 : Compilation of BH and host properties (Bohn+, 2020)
J/ApJ/901/133 : Supermassive BH masses of RM AGNs (Yu+, 2020)
J/ApJ/918/50 : Reverberation mapping for Mrk 817 and NGC 7469 (Lu+, 2021)
J/other/Ap/64.277 : Catalog of X-ray active galactic nuclei (Paronyan+, 2021)
J/MNRAS/510/4796 : INTEGRAL/IBIS 17yr hard X-ray survey (Krivonos+, 2022)
J/ApJ/927/42 : Sy1 AGNs with X-ray sp. from NuSTAR+Swift (Kamraj+, 2022)
J/A+A/682/A174 : Classification of Markarian galaxies (Mickaelian+, 2024)
J/A+A/687/A250 : STONKS Multi-Mission X-ray Catalog (Quintin+, 2024)
J/A+A/691/A203 : Multiwavelength properties of unobscured AGN (Gupta+, 2024)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 d HJD [9181/9636.8] Heliocentric Julian Date;
HJD-24500000
9- 12 F4.2 ct/s CRate [0.75/10] The 0.4-8keV count rate
14- 17 F4.2 ct/s e_CRate [0.02/0.12] Uncertainty in CRate
19- 23 F5.2 --- HR [-0.94/-0.47] Hardness ratio (1)
25- 28 F4.2 --- e_HR [0.01/0.06] Uncertainty in HR
--------------------------------------------------------------------------------
Note (1): HR=(H-S)/(H+S) where H=3-8keV and S=0.4-3keV count rates.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 d HJD [9181/9637] Heliocentric Julian Date;
HJD-24500000
9- 15 F7.3 mW/m2 logFO [-12.04/-10.69] Log obscured 0.4-8keV flux;
erg/s/cm2
17- 21 F5.3 mW/m2 E_logFO [0.008/0.1] Upper 68% confidence interval in
logFO
23- 27 F5.3 mW/m2 e_logFO [0.008/0.11] Lower 68% confidence interval
in logFO
29- 35 F7.3 mW/m2 logFU [-11.77/-10.5] Log unobscured 0.4-8keV flux;
erg/s/cm2
37- 41 F5.3 mW/m2 E_logFU [0.018/0.4] Upper 68% confidence interval in
logFU
43- 47 F5.3 mW/m2 e_logFU [0.015/0.3] Lower 68% confidence interval in
logFU
49- 53 F5.3 --- Frac [0.15/0.8] Fractional transmittance
55- 59 F5.3 --- E_Frac [0.018/1] Upper 68% confidence interval in
Frac
61- 65 F5.3 --- e_Frac [0.018/0.3] Lower 68% confidence interval in
Frac
67- 71 F5.2 10+22/cm2 NH [2.8/30] Obscurer Hydrogen column density
73- 77 F5.2 10+22/cm2 E_NH [0/10] Upper 68% confidence interval in NH
79- 83 F5.2 10+22/cm2 e_NH [0/21] Lower 68% confidence interval in NH
85- 90 F6.3 [-] logxi [-0.5/2.2] Log ionization parameter; L/nR2
92- 96 F5.3 [-] E_logxi [0/1.7] Upper 68% confidence interval in
logxi
98- 102 F5.3 [-] e_logxi [0/1.31] Lower 68% confidence interval in
logxi
104- 108 F5.3 --- cvf [0.7/1] Obscurer covering factor
110- 114 F5.3 --- E_cvf [0/0.07] Upper 68% confidence interval in cvf
116- 120 F5.3 --- e_cvf [0/0.1] Lower 68% confidence interval in cvf
122- 125 F4.2 --- chi2 [0.6/2] Best fit χ2ν value
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 d HJD [9189.2/9599.5] Heliocentric Julian Date;
HJD-24500000
9- 12 F4.2 ct/s 3C50-SR [0.5/10]? The "3C50" estimator 0.4-8keV source
rate (1)
14- 17 F4.2 ct/s e_3C50-SR [0.02/0.2]? Uncertainty in 3C50-SR (1)
19- 22 F4.2 ct/s 3C50-BR [0.27/2.8]? The "3C50" estimator 0.4-8keV
background rate (1)
24- 28 F5.2 ct/s ML-SR [0.2/14.1]? Machine learning estimator 0.4-8keV
source rate (1)
30- 33 F4.2 ct/s e_ML-SR [0.02/0.2]? Uncertainty in ML-SR (1)
35- 39 F5.2 ct/s ML-BR [0.3/14.4]? Machine learning estimator 0.4-8keV
background rate (1)
41- 45 F5.2 ct/s SW-SR [-1/27.5]? Space weather estimator 0.4-8keV
source rate (1)
47- 50 F4.2 ct/s e_SW-SR [0.02/0.16]? Uncertainty in SW-SR (1)
52- 55 F4.2 ct/s SW-BR [0.27/2.5]? Space weather estimator 0.4-8keV
background rate (1)
--------------------------------------------------------------------------------
Note (1): A blank indicates a case where the estimator failed or filtering
reduced the exposure below 400 seconds.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Kara et al. Paper I. 2021ApJ...922..151K 2021ApJ...922..151K
Homayouni et al. Paper II. 2023ApJ...948...85H 2023ApJ...948...85H
Partington et al. Paper III. 2023ApJ...947....2P 2023ApJ...947....2P This catalog
Cackett et al. Paper IV. 2023ApJ...958..195C 2023ApJ...958..195C
Homayouni et al. Paper V. 2024ApJ...963..123H 2024ApJ...963..123H
Neustadt et al. Paper VI. 2024ApJ...961..219N 2024ApJ...961..219N
Lewin et al. Paper VII. 2024ApJ...974..271L 2024ApJ...974..271L
DEHGHANIAN et al. Paper VIII. 2024ApJ...972..141D 2024ApJ...972..141D
ZAIDOUNI et al. Paper IX. 2024ApJ...974...91Z 2024ApJ...974...91Z
Netzer et al. Paper X. 2024ApJ...976...59N 2024ApJ...976...59N
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Mar-2025