Reverberation Mapping of High-Luminosity Quasars: First Results

By S. Kaspi, W. N. Brandt, D. Maoz, H. Netzer, D. P. Schneider, O. Shemmer. 2006

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Reverberation mapping of nearby active galactic nuclei (AGNs) has led to estimates of broad-line region (BLR) sizes and central object masses for some 37 objects to date. However, successful reverberation mapping has yet to be performed for quasars of either high luminosity (above Lopt ~ 1046 ergs s-1) or high redshift (z ≳ 0.3). Over the past 6 years, we have carried out, at the Hobby-Eberly Telescope, rest-frame ultraviolet spectrophotometric monitoring of a sample of six quasars at redshifts z = 2.2-3.2, with luminosities of Lopt ~ 1046.4-1047.6 ergs s-1, an order of magnitude greater than those of previously mapped quasars. The six quasars, together with an additional five having similar redshift and luminosity properties, were monitored photometrically at the Wise Observatory during the past decade. All 11 quasars monitored show significant continuum variations of order 10%-70%. This is about a factor of 2 smaller variability than for lower luminosity quasars monitored over the same rest-frame period. In the six objects that have been spectrophotometrically monitored, significant variability is detected in the C IV λ1550 broad emission line. In several cases the variations track the continuum variations in the same quasar, with amplitudes comparable to, or even greater than, those of the corresponding continua. In contrast, no significant Lyα variability is detected in any of the four objects in which it was observed. Thus, UV lines may have different variability trends in high-luminosity and low-luminosity AGNs. For one quasar, S5 0836+71 at z = 2.172, we measure a tentative delay of 595 days between C IV and UV continuum variations, corresponding to a rest-frame delay of 188 days and a central black hole mass of 2.6 × 109 M☉.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1a0c84bcfc9734cbb66bb2d49bacfb2f8477752c

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Citations in the corpus

LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, background): “Observations over a decade would enable the study of long period variables and quasars (Kaspi et al. 2007; MacLeod et al. 2010; Graham et al. 2014).”
Large Synoptic Survey Telescope: From Science Drivers to Reference Design (2008, background): “Time scales ranging from 1 min (to constrain the properties of fast faint transients such as optical flashes associated with gammaray bursts (Kaspi et al. 2007) and transients recently discovered by the Deep Lens Survey, Becker et al. 2004) to 10 years (to study long-period variables and quasars)…”
GeV BREAKS IN BLAZARS AS A RESULT OF GAMMA-RAY ABSORPTION WITHIN THE BROAD-LINE REGION (2010, methodology): “Reverberation mapping of Seyfert galaxies and quasars using the CIV λ1549 line showed that the size of the BLR scales with the luminosity as (Kaspi et al. 2007) RCIV,18 ≈ 0.4L 1/2 47 .”
Black Hole Masses and Enrichment of z ~ 6 SDSS Quasars (2007, background): “The most direct measurements of central black holes mass in AGN come from reverbaration mapping studies (e.g., Peterson et al. 2004; Kaspi et al. 2007), but these time intensive observations are not easily feasible for very distant QSOs.”
Measuring the Masses of Supermassive Black Holes (2014, background): “There are, however, a limited number observations that seem to 16 indicate that a relationship similar to that between Hβ and the AGN optical continuum holds for C ivλ1549 and the UV continuum as well (Kaspi et al. 2007).”
The blazar sequence: a new perspective (2008, positive): “(iii) More recently, Kaspi et al. (2007) considered the C IV line and the continuum at 1350 Å, deriving RBLR 10 light days = (0.17 ± 0.04) [ λLλ(1350 Å) 1043 erg s−1 ]0.52±0.04 .”
The Sloan Digital Sky Survey Reverberation Mapping Project: Hα and Hβ Reverberation Measurements from First-year Spectroscopy and Photometry (2017, background): “RM measurements have established the radiusluminosity (R − L) relationship (e.g., Kaspi et al. 2007; Bentz et al. 2013), which allows one to estimate the BLR size with a single spectrum and thus estimate MBH for large numbers of quasars at greater distances where traditional RM campaigns are…”
The Hard X-Ray Spectrum as a Probe for Black Hole Growth in Radio-Quiet Active Galactic Nuclei (2008, background): “…case, since our sources are mostly luminous and thus have smaller amplitudes of X-ray and optical flux variations (e.g., Lawrence & Papadakis 1993; Kaspi et al. 2007).7 To test whetherΓ can serve as an accretion-rate indicator we switched the roles ofΓ andL/LEdd, allowing the first to serve as…”
The Effect of Radiation Pressure on Virial Black Hole Mass Estimates and the Case of Narrow-Line Seyfert 1 Galaxies (2008, background): “However, this technique is very demanding in terms of telescope time and it can be applied only to a few objects especially at high redshifts (Peterson et al. 2004; Kaspi et al. 2007).”
Black Hole Growth to z = 2 - I: Improved Virial Methods for Measuring M_BH and L/L_Edd (2012, methodology): “For the “Hβ×C IV ” and “Mg II×C IV ” sub-samples we assumed the reverberation-based relation of Kaspi et al. (2007): RBLR (C IV) = 107.2 ( L1450 1046ergs−1 )0.55 lt−days.”
THE SDSS-IV EXTENDED BARYON OSCILLATION SPECTROSCOPIC SURVEY: QUASAR TARGET SELECTION (2015, background): “…rare types of quasars, and precision studies of the quasar luminosity function (e.g. Vanden Berk et al. 2001; Inada et al. 2003; McLure & Dunlop 2004; Hennawi et al. 2006; Richards et al. 2006; York et al. 2006; Netzer & Trakhtenbrot 2007; Kaspi et al. 2007; Shen et al. 2008; Boroson & Lauer 2009).”
ESTIMATING BLACK HOLE MASSES IN ACTIVE GALACTIC NUCLEI USING THE Mg ii λ2800 EMISSION LINE (2009, background): “…large samples of AGNs, especially for luminous quasars at higher redshift that typically exhibit only slow and small-amplitude variability (e.g., Kaspi et al. 2007), with the assumption that the virial relation is independent of redshift and can be extrapolated to higher luminosities and masses.”
Biases in Virial Black Hole Masses: An SDSS Perspective (2007, background): “…hole masses for large numbers of objects at high redshifts and luminosities (where variability timescales are too long to measure easily; see the discussion in Kaspi et al. 2007), but theR− L relation has only been established in the luminosity range∼ 1042− 1046 erg s−1 and for redshifts z< 0.3.”
REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES (2010, background): “L relationship), and this coupled with time dilation effects make it difficult and particularly time-consuming to make such measurements out to high redshift (see Kaspi et al. 2007).”
FERMIGAMMA-RAY SPACE TELESCOPE OBSERVATIONS OF THE GAMMA-RAY OUTBURST FROM 3C454.3 IN NOVEMBER 2010 (2011, background): “2 pc from reverberation mapping (Kaspi et al. 2007; Bonnoli et al. 2011), we calculate τ γγ ( z em ), where z em is the distance of the emitting blob from the black hole (following Reimer 2007).”
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. IX. 10 New Observations of Reverberation Mapping and Shortened Hβ Lags (2018, methodology): “…technique has been applied to measure the BH masses for more than 100 objects by different campaigns (e.g., Peterson et al. 1993, 1998, 2002, 2004; Kaspi et al. 2000, 2007; Bentz et al. 2008, 2009; Denney et al. 2009; Barth et al. 2011, 2013, 2015; Rafter et al. 2011, 2013; Grier et al. 2012,…”
THE LOW-LUMINOSITY END OF THE RADIUS–LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI (2013, methodology): “L relationships for these lines could be defined and calibrated as accurately as we have achieved for Hβ (see Kaspi et al. 2007 for current progress on the C iv RBLR–”
The AGN Black Hole Mass Database (2014, background): “The observed time delay may be several years, leading to the necessity for decade-long monitoring campaigns (e.g., Kaspi et al. 2000, 2007).”
THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: TECHNICAL OVERVIEW (2014, background): “However, quasars with these long lags typically vary on longer timescales than the six month baseline in the SDSS-RM program (e.g., Kaspi et al. 2007).”