RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

Grupe, D.; Thomas, H. C.; Leighly, Karen M.

doi:10.1051/0004-6361:20010117

Cited by 49 publications

(75 citation statements)

References 36 publications

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“…These objects appear to be X-ray bright only once and then get fainter or even vanish when observed years later. This phenomenon has been observed in NLS1, such as WPVS007 (Grupe et al 1995b) or RX J0134.2+4258 (Grupe et al 2000, and these proceedings). However, it is not specific to NLS1.…”

Section: X-ray Transiencesupporting

confidence: 53%

Statistical properties of narrow-line Seyfert 1 galaxies

Grupe

2000

New Astronomy Reviews

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The number of publications considering Narrow-Line Seyfert 1 galaxies has increased dramatically in recent years. Especially after the launch of the X-ray missions ROSAT and ASCA, Narrow-Line Seyfert 1s have become very popular. In these proceedings I will give an overview of how they are distributed over the electromagnetic spectrum. I will describe what we know about them at radio, infrared, optical, and X-ray bands, and how they differ and how they are similar to Broad-Line Seyfert 1s. Finally I will introduce a method to find them with high probability.

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Section: X-ray Transiencesupporting

confidence: 53%

Statistical properties of narrow-line Seyfert 1 galaxies

Grupe

2000

New Astronomy Reviews

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“…11. The spectral slope of a single power-law, absorbed by the galactic column and intrinsic absorption, plotted against X-ray luminosity: SWIFT J164449.3+573451 (Burrows et al 2011), SDSS J1201+30 and NGC 3599 (this work), NGC 5905 (Bade et al 1996), RXJ 1242.6-1119 (Komossa & Greiner 1999; this fit only uses Galactic absorption), RXJ 1624+7554 (Grupe et al 1999). …”

Section: Tidal Disruptionmentioning

confidence: 93%

A tidal disruption-like X-ray flare from the quiescent galaxy SDSS J120136.02+300305.5

Saxton

Read

Esquej

et al. 2012

A&A

147

131

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Aims. The study of tidal disruption flares from galactic nuclei has historically been hampered by a lack of high quality spectral observations taken around the peak of the outburst. Here we introduce the first results from a program designed to identify tidal disruption events at their peak by making near-real-time comparisons of the flux seen in XMM-Newton slew sources with that seen in ROSAT. Methods. Flaring extragalactic sources, which do not appear to be AGN, are monitored with Swift and XMM-Newton to track their temporal and spectral evolution. Timely optical observations are made to monitor the reaction of circumnuclear material to the X-ray flare.Results. SDSS J120136.02+300305.5 was detected in an XMM-Newton slew from June 2010 with a flux 56 times higher than an upper limit from ROSAT, corresponding to L X ∼ 3 × 10 44 erg s −1 . It has the optical spectrum of a quiescent galaxy (z = 0.146). Overall the X-ray flux has evolved consistently with the canonical t −5/3 model, expected for returning stellar debris, fading by a factor ∼300 over 300 days. In detail the source is very variable and became invisible to Swift between 27 and 48 days after discovery, perhaps due to self-absorption. The X-ray spectrum is soft but is not the expected tail of optically thick thermal emission. It may be fit with a Bremsstrahlung or double-power-law model and is seen to soften with time and declining flux. Optical spectra taken 12 days and 11 months after discovery indicate a deficit of material in the broad line and coronal line regions of this galaxy, while a deep radio non-detection implies that a jet was not launched during this event.

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“…TDE are most spectacular in the X-ray band where the contrast between the low-level X-ray emission of the host galaxy and the huge accretion flare, can reach factors of 1000s Halpern, Gezari & Komossa 2004;Komossa 2005). TDE were first identified from soft Xray flares seen in optically quiescent galaxies by the ROSAT mission (Bade, Komossa & Dahlem 1996;Komossa & Greiner 1999;Komossa & Bade 1999;Grupe et al 1999;Greiner et al 2000). A small number have also been detected in higher-energy Xrays by Swift (Burrows et al 2011;Bloom et al 2011;Cenko et al 2012a;Pasham et al 2015) and INTEGRAL (Nikolajuk & Walter 2013) while new soft-X-ray TDE have been identified by comparing XMM-Newton slew survey data with earlier ROSAT data (Esquej et al 2007; Saxton et al 2012) and by other X-ray ⋆ E-mail: richard.saxton@sciops.esa.int searches (Cappelluti et al 2009;Maksym et al 2010;Lin et al 2011;Maksym, Lin & Irwin 2014;Khabibullin & Sazonov 2014).…”

Section: Introductionmentioning

confidence: 99%

Was the soft X-ray flare in NGC 3599 due to an AGN disc instability or a delayed tidal disruption event?

Saxton

Motta

Komossa

et al. 2015

Mon. Not. R. Astron. Soc.

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We present unpublished data from a tidal disruption candidate in NGC 3599 which show that the galaxy was already X-ray bright 18 months before the measurement which led to its classification. This removes the possibility that the flare was caused by a classical, fast-rising, short-peaked, tidal disruption event. Recent relativistic simulations indicate that the majority of disruptions will actually take months or years to rise to a peak, which will then be maintained for longer than previously thought. NGC 3599 could be one of the first identified examples of such an event. The optical spectra of NGC 3599 indicate that it is a low-luminosity Seyfert/LINER with L bol ∼ 10 40 ergs s −1 . The flare may alternatively be explained by a thermal instability in the accretion disc, which propagates through the inner region at the sound speed, causing an increase of the disc scale height and local accretion rate. This can explain the 9 years rise time of the flare. If this mechanism is correct then the flare may repeat on a timescale of several decades as the inner disc is emptied and refilled.

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RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy

Cited by 49 publications

References 36 publications

Statistical properties of narrow-line Seyfert 1 galaxies

Statistical properties of narrow-line Seyfert 1 galaxies

A tidal disruption-like X-ray flare from the quiescent galaxy SDSS J120136.02+300305.5

Was the soft X-ray flare in NGC 3599 due to an AGN disc instability or a delayed tidal disruption event?

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