J/ApJ/909/159 Spectroscopic monitoring of IRAS F01004-2237 (Cannizzaro+, 2021)
Spectroscopic monitoring of the candidate tidal disruption event in F01004-2237.
Cannizzaro G., Jonker P.G., Mata-Sanchez D.
<Astrophys. J., 909, 159 (2021)>
=2021ApJ...909..159C 2021ApJ...909..159C
ADC_Keywords: Galaxies, IR; Spectra, optical; Active gal. nuclei
Keywords: Tidal disruption ; Active galactic nuclei ;
Ultraluminous infrared galaxies ; Transient sources ;
High energy astrophysics
Abstract:
We present results of spectroscopic monitoring observations of the
ultraluminous infrared galaxy F01004-2237. This galaxy was observed to
undergo changes in its optical spectrum, detected by comparing a
spectrum from 2015 with one from 2000. These changes were coincident
with photometric brightening. The main changes detected in the optical
spectrum are enhanced HeIIλ4686 emission and the appearance of
HeIλ3898,λ5876 emission lines. The favored
interpretation of these changes was that of a tidal disruption event
(TDE) happening in 2010. However, subsequent work suggested that these
changes are caused by another hitherto unknown effect related to
variations in the accretion rate in the active galactic nucleus (AGN).
Our optical spectroscopic monitoring observations show that the
evolution of the He lines is in line with the evolution seen in TDEs
and opposite of what is observed from reverberation-mapping studies of
AGNs, renewing the discussion of the interpretation of the flare as a
TDE.
Description:
Optical spectra of F01004-2237 were acquired with the Intermediate
dispersion Spectrograph and Imaging System (ISIS) and the
Auxiliary-port CAMera (ACAM) spectrographs, mounted at the Cassegrain
focus of the William Herschel Telescope (WHT), and the Device
Optimized for the LOw RESolution (DOLORES), installed at the Nasmyth B
focus of the Telescopio Nazionale Galileo (TNG). Both telescopes are
part of the Roque de los Muchachos observatory (La Palma, Spain).
We also reanalyzed the ISIS spectrum originally reported in T17
(Tadhunter+ 2017NatAs...1E..61T 2017NatAs...1E..61T) and added two epochs of observations
retrieved from the WHT archive to the sample of spectra we report on
here.
Overall, these spectra were taken over a period spanning 2015-2020
September.
In the case of ISIS, different grisms with different resolutions
(R300B and R600B for the blue arm and R158R, R316R, and R600R for the
red arm) were used, while ACAM was always used in combination with the
V400 grism and the GG395 order-sorting filter, and DOLORES was used
with the LR-B grism.
We finally also included the spectrum taken on 2000 February 9 with
the Space Telescope Imaging Spectrograph (STIS) on board the Hubble
Space Telescope (HST), retrieved from the online archive (gratings
G430L and G750L).
Objects:
------------------------------------------------------------
RA (ICRS) DE Designation(s)
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01 02 49.99 -22 21 57.3 F01004-2237 = IRAS F01004-2237
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 53 30426 The sequence of spectra under study in this paper
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
II/338 : IRAS PSC/FSC Combined Catalogue (Abrahamyan+ 2015)
J/ApJ/613/682 : AGN masses & broad-line region sizes (Peterson+, 2004)
J/MNRAS/398/109 : Imperial IRAS-FSC redshift catalogue (IIFSCz) (Wang+, 2009)
J/ApJS/182/628 : Spitzer quasar and ULIRG evolution study (Veilleux+, 2009)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/ApJ/698/1682 : Most luminous dusty galaxies (Weedman+, 2009)
J/ApJ/709/884 : Role of starburst-AGNs in LIRG mergers (Yuan+, 2010)
J/ApJ/730/19 : IR spectra and SEDs for starbursts and AGNs (Sargsyan+, 2011)
J/ApJ/793/38 : Palomar Transient Factory photometric obs. (Arcavi+, 2014)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "Y/M/D" Date Date of the observation
12- 25 A14 --- Tel Telescope/instrument used (1)
27- 33 F7.2 0.1nm lambda [3177/9057.2] Wavelength in Angstroms (2)
35- 41 F7.4 --- Flux [-1.49/14.54] Normalized flux
43- 53 E11.4 --- e_Flux [0.007/2.2] Uncertainty in Flux
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Note (1): Telescope/Instrument as follows:
HST-G43 = HST-STIS, G430L on 2000/02/09 (MJD51583.73); 898 occurrences
HST-G75 = HST-STIS, G750L on 2000/02/09 (MJD51583.73); 538 occurrences
TNGDOLORES = TNG-DOLORES, LR-B grating on 2020/09/24 (MJD59117.10);
1496 occurrences
WHT-ACAM = WHT-ACAM, V400 grating on 2019/07/24 (MJD58689.20);
1491 occurrences
WHT-ACAMo = WHT-ACAM, V400 grating on 2019/07/26 (MJD58691.20;
1441 occurrences) and 2019/12/08 (MJD58825.82; 1391 occurrences)
WHT-ISIS-R158R = WHT-ISIS, R158R grating on 2018/08/14 (MJD58345.15;
1936 occurrences) and 2018/08/24 (MJD58355.22;
1701 occurrences)
WHT-ISIS-R300B = WHT-ISIS, R300B grating on 2015/09/15, 2017/09/14, 2017/09/15,
2018/08/14, 2018/08/24 and 2019/09/03
WHT-ISIS-R316R = WHT-ISIS, R316R grating on 2015/09/15, 2017/08/30, 2019/09/03,
2019/09/04
WHT-ISIS-R600B = WHT-ISIS, R600B grating on 2017/10/26 (MJD58052.99;
1651 occurrences)
WHT-ISIS-R600R = WHT-ISIS, R600R grating on 2017/10/26 (MJD58052.99;
1291 occurrences)
Note (2): These spectra have not been corrected for the redshift of F01004-2237.
The spectra shown in Figure 1 have a z=0.118 correction applied.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Aug-2022