J/ApJ/948/85 AGN STORM 2. II. HST/COS UV obs. of Mrk817 (Homayouni+, 2023)
AGN STORM 2.
II. Ultraviolet observations of Mrk 817 with the Cosmic Origins Spectrograph
on the Hubble Space Telescope.
Homayouni Y., De Rosa G., Plesha R., Kriss G.A., Barth A.J., Cackett E.M.,
Horne K., Kara E.A., Landt H., Arav N., Boizelle B.D., Bentz M.C.,
Brink T.G., Brotherton M.S., Chelouche D., Dalla Bonta E., Dehghanian M.,
Du Pu, Ferland G.J., Ferrarese L., Fian C., Filippenko A.V., Fischer T.,
Foley R.J., Gelbord J., Goad M.R., Gonzalez Buitrago D.H., Gorjian V.,
Grier C.J., Hall P.B., Hernandez Santisteban J.V., Hu C., Ilic D.,
Joner M.D., Kaastra J., Kaspi S., Kochanek C.S., Korista K.T.,
Kovacevic A.B., Kynoch D., Li Y.-R., McHardy I.M., McLane J.N.,
Mehdipour M., Miller J.A., Mitchell J., Montano J., Netzer H.,
Panagiotou C., Partington E., Pogge R.W., Popovic L. C, Proga D.,
Rogantini D., Storchi-Bergmann T., Sanmartim D., Siebert M.R., Treu T.,
Vestergaard M., Wang J.-M., Ward M.J., Waters T., Williams P.R.,
Zaidouni F., Zu Y.
<Astrophys. J., 948, 85 (2023)>
=2023ApJ...948...85H 2023ApJ...948...85H
ADC_Keywords: Active gal. nuclei; Spectra, ultraviolet
Keywords: Active galactic nuclei ; Reverberation mapping ; Active galaxies ;
Seyfert galaxies
Abstract:
We present reverberation mapping measurements for the prominent
ultraviolet broad emission lines of the active galactic nucleus Mrk817
using 165 spectra obtained with the Cosmic Origins Spectrograph on the
Hubble Space Telescope. Our ultraviolet observations are accompanied
by X-ray, optical, and near-infrared observations as part of the AGN
Space Telescope and Optical Reverberation Mapping Program 2 (AGN
STORM 2). Using the cross-correlation lag analysis method, we find
significant correlated variations in the continuum and emission-line
light curves. We measure rest-frame delayed responses between the
far-ultraviolet continuum at 1180Å and Lyαλ1215Å
(10.4-1.4+1.6days), NVλ1240Å (15.5-4.8+1.0days),
SiIV+]OIVλ1397Å (8.2-1.4+1.4days), CIVλ1549Å
(11.8-2.8+3.0days), and HeIIλ1640Å (9.0-1.9+4.5days)
using segments of the emission-line profile that are unaffected by
absorption and blending, which results in sampling different velocity
ranges for each line. However, we find that the emission-line
responses to continuum variations are more complex than a simple
smoothed, shifted, and scaled version of the continuum light curve. We
also measure velocity-resolved lags for the Lyα and CIV emission
lines. The lag profile in the blue wing of Lyα is consistent
with virial motion, with longer lags dominating at lower velocities,
and shorter lags at higher velocities. The CIV lag profile shows the
signature of a thick rotating disk, with the shortest lags in the
wings, local peaks at ±1500km/s, and a local minimum at the line
center. The other emission lines are dominated by broad absorption
lines and blending with adjacent emission lines. These require
detailed models, and will be presented in future work.
Description:
Mrk 817 was observed with HST COS over 165 epochs with a median
cadence of 2 days from 2020 November 24 to 2022 February 24. These
data are available from MAST: doi:10.17909/10sp-zt74. We obtained
high-resolution COS spectra in single-orbit visits using the G130M
(10000<R<15000) and G160M (13000<R<24000) gratings to obtain far-UV
(FUV) spectra covering 1070-1750Å. For each visit, we obtained four
60s exposures with the G130M grating centered at 1222Å, two
exposures of 175 and 180s using the G160M grating centered at
1533Å, and two 195s exposures with G160M at 1577Å. These
exposure times ensure an S/N∼10 per resolution element in the
continuum at 1180 and 1502Å.
In addition to the COS spectra, we dedicated six additional orbits to
obtain low-resolution spectra using the STIS/NUV-MAMA and the STIS CCD
to capture full spectra from the FUV to the near-IR. We used gratings
G230L, G430L, and G750L in 2-orbit visits paired with COS observations
to cover the range of 940-10200Å. These visits were evenly
distributed throughout the campaign and they were coordinated with
XMM-Newton observations.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
14 36 22.08 +58 47 39.3 Mrk 817 = UGC 9412
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 59 165 Continuum light curves
table5.dat 68 165 Emission-line light curves
--------------------------------------------------------------------------------
See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2012-)
J/A+A/639/L13 : 4C 41.17 IRAM/NOEMA data cubes (Nesvadba+, 2020))
J/ApJS/105/369 : Galactic H I column densities (Murphy+ 1996)
J/ApJ/599/886 : Emission lines of radio-loud AGN (Eracleous+, 2003)
J/AJ/126/1720 : ugriz and Hα of double-peaked AGN (Strateva+, 2003)
J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJ/732/121 : V-band and Hβ monitoring of Z299-15 (Barth+, 2011)
J/ApJ/753/106 : Quasar variability with SDSS and POSS imaging (MacLeod+, 2012)
J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)
J/ApJ/806/128 : Space telescope RM project. I. NGC5548 (De Rosa+, 2015)
J/ApJ/806/129 : Space telescope RM project. II. Swift data (Edelson+, 2015)
J/ApJ/821/56 : Space telescope RM project. III. LCs (Fausnaugh+, 2016)
J/ApJ/851/21 : SDSS RM project first year of observations (Grier+, 2017)
J/ApJ/837/131 : Space telescope RM project. V. NGC5548 sp. (Pei+, 2017)
J/ApJ/866/133 : Continuum-Hβ light curves of 5 Seyfert 1 (De Rosa+, 2018)
J/ApJ/869/142 : Monitoring AGNs with Hβ Asymmetry (MAHA). I. (Du+, 2018)
J/ApJ/881/153 : Space telescope RM project. VIII. HST sp. (Kriss+, 2019)
J/ApJ/905/77 : Monitoring AGNs with Hb Asymmetry. II. (Brotherton+, 2020)
J/ApJ/890/71 : 5100Å cont. & emission lines LCs of PG2130+099 (Hu+, 2020)
J/ApJS/262/14 : AGNs with Hβ asymmetry. III. 15 PG quasars (Bao+, 2022)
J/ApJ/925/52 : LAMP 2016: velocity-resolved Hb lags in Seyfert (U+, 2022)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD [59177.7/59634.4] Mid-point of G130M and
G160M observations, HJD-2400000
12- 17 F6.2 10-17W/m2/nm F1180 [42/110] F1180 Continuum FLux,
10-15ergs/s/cm2/Å
19- 23 F5.3 10-17W/m2/nm e_F1180 [0.3/0.8] Error in F1180 Continuum FLux
25- 29 F5.2 10-17W/m2/nm F1398 [38.8/89] F1398 Continuum Flux,
10-15ergs/s/cm2/Å
31- 35 F5.3 10-17W/m2/nm e_F1398 [0.3/0.5] Error in F1398 Continuum Flux
37- 41 F5.2 10-17W/m2/nm F1502 [34.3/80] F1502 Continuum Flux,
10-15ergs/s/cm2/Å
43- 47 F5.3 10-17W/m2/nm e_F1502 [0.2/0.4] Error in F1502 Continuum Flux
49- 53 F5.2 10-17W/m2/nm F1739 [28/69] F1739 Continuum Flux,
10-15ergs/s/cm2/Å
55- 59 F5.3 10-17W/m2/nm e_F1739 [1/1.8] Error in F1739 Continuum Flux
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD [59177.7/59634.4] Mid-point of G130M and
G160M observations, HJD-2400000
12- 16 F5.2 10-13mW/m2 Lya [7.6/16.2] Integrated Lyα Line
FLux, 10-13erg/s/cm2 (1)
18- 22 F5.3 10-13mW/m2 e_Lya [0.06/0.2] Error in integrated Line FLux
24- 28 F5.2 10-13mW/m2 NV [10.3/22.3] Integrated NV Line FLux,
10-13erg/s/cm2 (1)
30- 34 F5.3 10-13mW/m2 e_NV [0.08/0.2] Error in integrated Line FLux
36- 39 F4.2 10-13mW/m2 SiIV+OIV [3.5/8.5] Integrated SiIV+OIV Line FLux,
10-13erg/s/cm2 (1)
41- 45 F5.3 10-13mW/m2 e_SiIV+OIV [0.09/0.2] Error in integrated Line FLux
47- 51 F5.2 10-13mW/m2 CIV [17.5/29.1] Integrated C IV Line FLux,
10-13erg/s/cm2 (1)
53- 57 F5.3 10-13mW/m2 e_CIV [0.2/0.4] Error in integrated Line FLux
59- 62 F4.2 10-13mW/m2 HeII [1.6/4] Integrated He II Line FLux,
10-13erg/s/cm2 (1)
64- 68 F5.3 10-13mW/m2 e_HeII [0.15/0.3] Error in integrated Line FLux
--------------------------------------------------------------------------------
Note (1): The flux measurements reported here are only a fraction of
the total line flux due to contamination by absorption and
blending (see the reported fractions in Table 2).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-May-2025