Multi-Wavelength Monitoring and Reverberation Mapping of a Changing Look Event in the Seyfert Galaxy NGC 3516

Abstract We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-ray to the optical. The facilities included the telescopes of the CMO SAI MSU, the 2.3-m WIRO telescope, and the XRT and UVOT of Swift. We found that NGC 3516 brightened to a high state and could be classified as Sy1.5 during the late spring of 2020. We have measured time delays in the responses of the Balmer and He II λ4686 lines to continuum variations. In the case of the best-characterized broad Hβ line, the delay to continuum variability is about 17 days in the blue wing and is clearly shorter, 9 days, in the red, which is suggestive of inflow. As the broad lines strengthened, the blue side came to dominate the Balmer lines, resulting in very asymmetric profiles with blueshifted peaks during this high state. During the outburst the X-ray flux reached its maximum on 1 April 2020 and it was the highest value ever observed for NGC 3516 by the Swift observatory. The X-ray hard photon index became softer, ∼1.8 in the maximum on 21 Apr 2020 compared to the mean ∼0.7 during earlier epochs before 2020. We have found that the UV and optical variations correlated well (with a small time delay of 1–2 days) with the X-ray until the beginning of April 2020, but later, until the end of Jun. 2020, these variations were not correlated. We suggest that this fact may be a consequence of partial obscuration by Compton-thick clouds crossing the line of sight.

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Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4−650224

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834835 ◽

2019 ◽

Vol 622 ◽

pp. A211 ◽

Cited By ~ 10

Author(s):

Francesco Coti Zelati ◽

Alessandro Papitto ◽

Domitilla de Martino ◽

David A. H. Buckley ◽

Alida Odendaal ◽

...

Keyword(s):

Gamma Ray ◽

Broad Band ◽

Optical Emission ◽

Bimodal Distribution ◽

X Ray ◽

The Past ◽

Upper Limits ◽

Photon Index ◽

Multi Wavelength ◽

Absorbed Power

We report on a multi-wavelength study of the unclassified X-ray source CXOU J110926.4−650224 (J1109). We identified the optical counterpart as a blue star with a magnitude of ∼20.1 (3300–10500 Å). The optical emission was variable on timescales from hundreds to thousands of seconds. The spectrum showed prominent emission lines with variable profiles at different epochs. Simultaneous XMM-Newton and NuSTAR observations revealed a bimodal distribution of the X-ray count rates on timescales as short as tens of seconds, as well as sporadic flaring activity. The average broad-band (0.3–79 keV) spectrum was adequately described by an absorbed power law model with photon index of Γ = 1.63 ± 0.01 (at 1σ c.l.), and the X-ray luminosity was (2.16 ± 0.04) × 1034 erg s−1 for a distance of 4 kpc. Based on observations with different instruments, the X-ray luminosity has remained relatively steady over the past ∼15 years. J1109 is spatially associated with the gamma-ray source FL8Y J1109.8−6500, which was detected with Fermi at an average luminosity of (1.5 ± 0.2) × 1034 erg s−1 (assuming the distance of J1109) over the 0.1–300 GeV energy band between 2008 and 2016. The source was undetected during ATCA radio observations that were simultaneous with NuSTAR, down to a 3σ flux upper limit of 18 μJy beam−1 (at 7.25 GHz). We show that the phenomenological properties of J1109 point to a binary transitional pulsar candidate currently in a sub-luminous accretion disk state, and that the upper limits derived for the radio emission are consistent with the expected radio luminosity for accreting neutron stars at similar X-ray luminosities.

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Black hole masses from X-rays

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312020455 ◽

2012 ◽

Vol 8 (S290) ◽

pp. 371-372

Author(s):

Xin-Lin Zhou ◽

Roberto Soria

Keyword(s):

Black Hole ◽

X Rays ◽

X Ray ◽

Reverberation Mapping ◽

Photon Index ◽

Bolometric Correction ◽

Black Hole Masses ◽

Intrinsic Scatter

AbstractWe discuss two methods to estimate black hole (BH) masses using X-ray data only: from the X-ray variability amplitude and from the photon index Γ. The first method is based on the anti-correlation between BH mass and X-ray variability amplitude. Using a sample of AGN with BH masses from reverberation mapping, we show that this method shows small intrinsic scatter. The second method is based on the correlation between Γ and both the Eddington ratio Lbol/LEdd and the bolometric correction Lbol/L2−10keV.

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Multi-wavelength Behaviour of III Zw2

Publications of the Astronomical Society of Australia ◽

10.1071/as01093 ◽

2002 ◽

Vol 19 (1) ◽

pp. 73-76

Author(s):

Nikita Salvi ◽

Mat J. Page ◽

Jason A. Stevens ◽

Keith O. Mason ◽

Kinwah Wu

Keyword(s):

Synchrotron Radiation ◽

Optical Emission ◽

High Energy ◽

X Rays ◽

X Ray ◽

High Energy Electrons ◽

Photon Index ◽

Multi Wavelength ◽

Wavelength Light ◽

Gaussian Line

AbstractIII Zw2 was observed with XMM-Newton in July 2000. Its X-ray spectrum can be described by a power law of photon index Γ≈1.7 with a Gaussian line at 6.7 KeV. There is no significant evidence of intrinsic absorption within the source or of a soft X-ray excess. Multi-wavelength light curves over a period of 25 years show related variations from the radio to X-rays. We interpret the radio to optical emission as synchrotron radiation, self-absorbed in the radio/millimetre region, and the X-rays as mainly due to Compton up-scattering of low energy photons by the population of high energy electrons that give rise to the synchrotron radiation.

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Multi-wavelength campaign on NCG 7469

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832726 ◽

2018 ◽

Vol 615 ◽

pp. A163 ◽

Cited By ~ 19

Author(s):

R. Middei ◽

S. Bianchi ◽

M. Cappi ◽

P.-O. Petrucci ◽

F. Ursini ◽

...

Keyword(s):

Spectral Analysis ◽

Optical Depth ◽

Spherical Geometry ◽

Relativistic Effects ◽

Seyfert Galaxy ◽

High Energy ◽

Joint Analysis ◽

Photon Index ◽

Multi Wavelength ◽

Average Flux

We conducted a multi-wavelength 6-month campaign to observe the Seyfert Galaxy NGC 7469, using the space-based observatories HST, Swift, XMM-Newton and NuSTAR. We report the results of the spectral analysis of the seven simultaneous XMM-Newton and NuSTAR observations. The source shows significant flux variability within each observation, but the average flux is less variable among the different pointings of our campaign. Our spectral analysis reveals a prominent narrow neutral Fe Kα emission line in all the spectra and weaker contributions from Fe Kβ, neutral Ni Kα, and ionized iron. We find no evidence for variability or relativistic effects acting on the emission lines, which indicates that they originate from distant material. In the joint analysis of XMM-Newton and NuSTAR data, a constant photon index is found (Γ = 1.78 ± 0.02) together with a high energy cut-off Ecut = 170−40+60 keV. Adopting a self-consistent Comptonization model, these values correspond to an average coronal electron temperature of kT = 45−12+15 keV and, assuming a spherical geometry, an optical depth τ = 2.6 ± 0.9. The reflection component is consistent with being constant and the reflection fraction is in the range R = 0.3−0.6. A prominent soft excess dominates the spectra below 4 keV. This is best fit with a second Comptonization component, arising from a warm corona with an average kT = 0.67 ± 0.03 keV and a corresponding optical depth τ = 9.2 ± 0.2.

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Properties of Warm Absorbers and Constraints from their Optical and UV Line Emission

International Astronomical Union Colloquium ◽

10.1017/s0252921100040197 ◽

1997 ◽

Vol 159 ◽

pp. 246-247

Author(s):

Stefanie Komossa ◽

Henner Fink

Keyword(s):

Line Emission ◽

Seyfert Galaxies ◽

Coronal Line ◽

X Ray ◽

Line Region ◽

High Ionization ◽

Photon Index ◽

Balmer Lines ◽

The Individual ◽

Ionization Parameter

We have studied the warm absorbers in several Seyfert galaxies using both PI and archival ROSAT data. The parameters that govern the emissivity of the ionized material, ionization parameter U, warm-absorber column density Nwa, and the source intrinsic power-law photon index Γx, are determined from X-ray spectral fits. These are then used to predict the expected IR to UV line emission of the ionized material in the individual objects. In particular, the possibility of a warm-absorber origin of one of the known emission-line regions in AGN is assessed. Good ‘candidate components’ are, e.g., the coronal-line region, and/or the high-ionization component of the NLR, or the component responsible for broad wings in the Balmer lines. All calculations have been carried out using the code CLOUDY (Ferland 1993).

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Reverberation Mapping Analysis of the Broad-Line Region in Seyfert Galaxy NGC 4151

Symposium - International Astronomical Union ◽

10.1017/s0074180900115840 ◽

1998 ◽

Vol 188 ◽

pp. 424-425

Author(s):

S.J. Xue ◽

F.Z. Cheng

Keyword(s):

Emission Line ◽

Time Lag ◽

Seyfert Galaxy ◽

Broad Line ◽

Reverberation Mapping ◽

Ngc 4151 ◽

Broad Line Region ◽

Spectroscopic Monitoring ◽

Line Region ◽

The Continuum

One of the primary goals of AGN variability studies has been to determine the size of broad-line region (BLR) through the reverberation mapping technique. In a recent international multiwavelength spectroscopic monitoring campaign, NGC 4151 has been observed intensively by ground-based telescopes for a period of over 2 months, with a typical temporal resolution of 1 day. The main result from this optical campaign is that finding the variation in the emission line flux (Hβ or Hα) lagging the continuum by 0-3 days (1993 campaign: Kaspi et al. 1996). This is in contrast to the past results in which a time lag of 9±2 days was found for the same emission line (1988 campaign: Maoz et al. 1991). Such a BLR “size problem” may be caused by a different variability timescale of the ionizing continuum or a real change in BLR gas distribution in the 5.5 yr interval between the two watch campaigns. In order to clarify which of the two possibilities is most likely the real case, we performed further reverberation analysis on both optical datasets.

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The role of AGN activity in the building up of the BCG at z ∼ 1.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320003105 ◽

2019 ◽

Vol 15 (S356) ◽

pp. 280-284

Author(s):

Angela Bongiorno ◽

Andrea Travascio

Keyword(s):

Galaxy Cluster ◽

Cluster Galaxy ◽

X Ray ◽

Groups Of Galaxies ◽

Star Forming ◽

The Core ◽

The Galaxy ◽

Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

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X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320002756 ◽

2019 ◽

Vol 15 (S356) ◽

pp. 143-143

Author(s):

Jaya Maithil ◽

Michael S. Brotherton ◽

Bin Luo ◽

Ohad Shemmer ◽

Sarah C. Gallagher ◽

...

Keyword(s):

Black Holes ◽

Black Hole ◽

Accretion Rate ◽

Time Lags ◽

Black Hole Mass ◽

Host Galaxies ◽

Massive Black Holes ◽

X Ray ◽

Photon Index ◽

The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

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X-ray Properties of 3C 111: Separation of Primary Nuclear Emission and Jet Continuum

Universe ◽

10.3390/universe6110219 ◽

2020 ◽

Vol 6 (11) ◽

pp. 219

Author(s):

Elena Fedorova ◽

B.I. Hnatyk ◽

V.I. Zhdanov ◽

A. Del Popolo

Keyword(s):

Accretion Disk ◽

Power Law ◽

Line Emission ◽

High Energy ◽

Power Law Model ◽

X Ray ◽

Additional Information ◽

Observational Dataset ◽

Simple Power ◽

Photon Index

3C111 is BLRG with signatures of both FSRQ and Sy1 in X-ray spectrum. The significant X-ray observational dataset was collected for it by INTEGRAL, XMM-Newton, SWIFT, Suzaku and others. The overall X-ray spectrum of 3C 111 shows signs of a peculiarity with the large value of the high-energy cut-off typical rather for RQ AGN, probably due to the jet contamination. Separating the jet counterpart in the X-ray spectrum of 3C 111 from the primary nuclear counterpart can answer the question is this nucleus truly peculiar or this is a fake “peculiarity” due to a significant jet contribution. In view of this question, our aim is to estimate separately the accretion disk/corona and non-thermal jet emission in the 3C 111 X-ray spectra within different observational periods. To separate the disk/corona and jet contributions in total continuum, we use the idea that radio and X-ray spectra of jet emission can be described by a simple power-law model with the same photon index. This additional information allows us to derive rather accurate values of these contributions. In order to test these results, we also consider relations between the nuclear continuum and the line emission.

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