Multiple flares in the changing-look AGN NGC 5273

Neustadt, Jack M. M.; Hinkle, J.; Kochanek, C. S.; Reynolds, M. T.; Mathur, S.; Tucker, M. A.; Rick, Pogge,; Stanek, K. Z.; Payne, A. V.; Shappee, B. J.; Holoien, T. W. S.; Auchettl, Katie; Ashall, C.; deJaeger, T; Desai, D.; Do, A.; Hoogendam, W. B.; Huber, M. E.

doi:10.1093/mnras/stad725

Cited by 5 publications

(3 citation statements)

References 163 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The majority of our targets show negative slopes, and some of them closely follow the virial relation. Similar trends are also reported for other CL AGNs (Green et al 2022;Zeltyn et al 2022;Neustadt et al 2023). Such results may suggest that the BLR can stay more or less virialized during the type transition, implying that CL AGNs are not likely caused by structural changes in BLRs.…”

Section: Eddington Ratiossupporting

confidence: 85%

“…At the same time, the unified model faces significant challenges, particularly with the discovery of a small population of AGNs with emerging/disappearing broad emission lines over timescales of several years. Approximately 150 such changing-look (CL) AGNs have been reported so far, based on Hβ and/or Hα (e.g., LaMassa et al 2015;MacLeod et al 2016MacLeod et al , 2019Ruan et al 2016;Runco et al 2016;Runnoe et al 2016;Yang et al 2018;Wang et al 2019;Green et al 2022;Hon et al 2022;López-Navas et al 2022, 2023bZeltyn et al 2022;Neustadt et al 2023;Guo et al 2024). These CL AGNs demonstrate that the orientation-based unified model might be too simplistic.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Identifying Changing-look AGNs Using Variability Characteristics

Wang,

Woo,

Gallo

et al. 2024

ApJ

View full text Add to dashboard Cite

Changing-look (CL) active galactic nuclei (AGNs), characterized by the appearance/disappearance of broad emission lines in the span of a few years, present a challenge for the AGN unified model, whereby the Type 1 versus Type 2 dichotomy results from orientation effects alone. We present a systematic study of a large sample of spectroscopically classified AGNs, using optical variability data from the Zwicky Transient Facility (ZTF) as well as follow-up spectroscopy data. We demonstrate that Type 1 and Type 2 AGNs can be neatly separated on the basis of the variability metric σ QSO, which quantifies the resemblance of a light curve to a damped random walk model. For a small subsample, however, the ZTF light curves are inconsistent with their previous classification, suggesting the occurrence of a CL event. Specifically, we identify 35 (12) turn-on (turn-off) CL AGN candidates at z < 0.35. Based on follow-up spectroscopy, we confirm 17 (4) turn-on (turn-off) CL AGNs out of 21 (5) candidates, representing a high success rate for our method. Our results suggest that the occurrence rate of CL AGNs is ∼0.3% over timescales of 5–20 yr, and confirm that the CL transition typically occurs at an Eddington ratio of ≲0.01.

show abstract

Section: Eddington Ratiossupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Identifying Changing-look AGNs Using Variability Characteristics

Wang,

Woo,

Gallo

et al. 2024

ApJ

View full text Add to dashboard Cite

show abstract

“…Such a symmetric light curve with respect to its maximum is difficult to explain by means of normal AGN variability with variable gas inflow onto the central black hole. Normal AGN light curves show uncorrelated flux variations 28,29,3,30,31 . Possible tidal disruption events (TDE's) show a steep increase followed by an exponential decrease 32 of the continuum flux.…”

mentioning

confidence: 99%

Gravitational self-lensing of the supermassive black hole binary in NGC1566

Kollatschny,

Probst,

Ochmann

et al. 2023

Preprint

View full text Add to dashboard Cite

It is generally accepted that all massive galaxies host supermassive black holes in their center1 and that mergers of two galaxies lead to the formation of black hole binaries2. The most interesting among them comprise the mergers in their final state, i.e. with pc (3.2 light years) or sub-pc orbital separations. Binary self-lensing is a possibility to detect these systems. Here we report the detection of a central supermassive black hole binary in the active galaxy (AGN) NGC1566 based on a microlensing outburst. The light curve of the outburst - based on observations with the All Sky Automated Survey for SuperNovae - lasted from the beginning of the year 2017 until the beginning of 2020. The shape of the symmetric light curve looks very different with respect to normal random variations of AGN3,4. However, it could be easily reproduced with a best-fit standard microlensing light curve5. Based on the light curve we derive a characteristic time-scale of 155 days. During the outburst, the continuum as well as the broad line intensities varied - however the narrow emission lines did not. This is an indication that the lensing object orbits the AGN nucleus between the broad line region and the narrow line region, i.e. at a distance on the order of 250 light days. The observed characteristic time-scale depends on the lens mass, the distances between lens and source, and the transverse velocity. The light curve can be reproduced by a lens with a black hole (BH) mass of 5x105 M⊙. This implies a mass ratio to the central AGN on the order of 1 to 10.

show abstract

Discovery and follow-up of ASASSN-23bd (AT 2023clx): the lowest redshift and luminosity optically selected tidal disruption event

Hoogendam,

Hinkle,

Shappee

et al. 2024

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report the All-Sky Automated Survey for SuperNovae discovery of the tidal disruption event (TDE) ASASSN-23bd (AT 2023clx) in NGC 3799, a LINER galaxy with no evidence of strong AGN activity over the past decade. With a redshift of z = 0.01107 and a peak UV/optical luminosity of (5.4 ± 0.4) × 1042 erg s−1, ASASSN-23bd is the lowest-redshift and least-luminous TDE discovered to date. Spectroscopically, ASASSN-23bd shows Hα and He i emission throughout its spectral time series, there are no coronal lines in its NIR spectrum, and the UV spectrum shows nitrogen lines without the strong carbon and magnesium lines typically seen for AGN. Fits to the rising ASAS-SN light curve show that ASASSN-23bd started to brighten on MJD 59988$^{+1}_{-1}$, ∼9 days before discovery, with a nearly linear rise in flux, peaking in the g band on MJD $60000^{+3}_{-3}$. Scaling relations and TDE light curve modelling find a black hole mass of ∼106 M⊙, which is on the lower end of supermassive black hole masses. ASASSN-23bd is a dim X-ray source, with an upper limit of L0.3 − 10 keV < 1.0 × 1040 erg s−1 from stacking all Swift observations prior to MJD 60061, but with soft (∼0.1 keV) thermal emission with a luminosity of L0.3 − 2 keV ∼ 4 × 1039 erg s−1 in XMM-Newton observations on MJD 60095. The rapid (t < 15 days) light curve rise, low UV/optical luminosity, and a luminosity decline over 40 days of ΔL40 ≈ −0.7 dex make ASASSN-23bd one of the dimmest TDEs to date and a member of the growing ‘Low Luminosity and Fast’ class of TDEs.

show abstract

Multiple flares in the changing-look AGN NGC 5273

Cited by 5 publications

References 163 publications

Identifying Changing-look AGNs Using Variability Characteristics

Identifying Changing-look AGNs Using Variability Characteristics

Gravitational self-lensing of the supermassive black hole binary in NGC1566

Discovery and follow-up of ASASSN-23bd (AT 2023clx): the lowest redshift and luminosity optically selected tidal disruption event

Contact Info

Product

Resources

About