Monitoring of the optical and 2.5-11.7 mu m spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk 279 with ISO
European Space Research and Technology Centre1, European Southern Observatory2, Harvard University3, University of Arizona4, Ohio State University5, Goddard Space Flight Center6, University of Leicester7, Tel Aviv University8, University of St Andrews9, Space Telescope Science Institute10, Johns Hopkins University11, University of California, Los Angeles12, Isaac Newton Institute13, Shanghai Astronomical Observatory14, European University of Madrid15
01 Apr 2001-Vol. 369, Iss: 1, pp 57-64
TL;DR: In this article, mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7 mum spectrum.
Abstract: Mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7 mum spectrum. Contemporaneous optical photometric and spectrophotometric observations are also presented. The galaxy appears as a point-like source at the resolution of the ISOCAM instrument (4-5 "). The 2.5-11.7 mum average spectrum of the nucleus in Mrk 279 shows a strong power law continuum with alpha = -0.80 +/- 0.05 (F nu proportional to nu (alpha)) and weak PAK emission features. The Mrk 279 spectral energy distribution shows a mid-IR bump, which extends from 2 to 15-20 mum The mid-IR bump is consistent with thermal emission from dust grains at a distance of greater than or similar to 100 It-d. No significant variations of the mid-IR flux have been detected during our observing campaign, consistent with the relatively low amplitude (similar to 10% rms) of the optical variability during the campaign. The time delay for H beta line emission in response to the optical continuum variations is tau = 16.7(-5.6)(+5.3), days, consistent with previous measurements.
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...…1998, Denney et al. 2006, 2010, Dietrich et al. 1993, 1998, 2012, Du et al. 2014, 2015, 2016, Grier et al. 2012, Kaspi et al. 2000, Korista et al. 1995, Pei et al. 2014, Peterson et al. 1991, 1992, 1994, 1998, 1999, 2002, 2014, Santos-Lleó et al. 1997, 2001, Stirpe et al. 1994, Wang et al. 2014)....
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TL;DR: In this article, the authors compared the predicted location of the inner radius of the Broad Line Region (BLR) in those two scenarios with the observed position obtained from the reverberation studies of several active galaxies.
Abstract: The origin of the Broad Line Region (BLR) in active galaxies remains unknown. It seems to be related to the underlying accretion disk but an efficient mechanism is required to rise the material from the disk surface without giving too strong signatures of the outflow in the case of the low ionization lines. We discuss in detail two proposed mechanisms: (i) radiation pressure acting on dust in the disk atmosphere creating a failed wind (ii) the gravitational instability of the underlying disk. We compare the predicted location of the inner radius of the BLR in those two scenarios with the observed position obtained from the reverberation studies of several active galaxies. The failed dusty outflow model well represents the observational data while the predictions of the self-gravitational instability are not consistent with observations. The issue remains why actually we do not see any imprints of the underlying disk instability in the BLR properties.
37 citations
TL;DR: In this article, a class of methods for measuring time delays between astronomical time series is introduced in the context of quasar reverberation mapping, which is based on measures of randomness or complexity of the data.
Abstract: A class of methods for measuring time delays between astronomical time series is introduced in the context of quasar reverberation mapping, which is based on measures of randomness or complexity of the data. Several distinct statistical estimators are considered that do not rely on polynomial interpolations of the light curves nor on their stochastic modeling, and do not require binning in correlation space. Methods based on von Neumann's mean-square successive-difference estimator are found to be superior to those using other estimators. An optimized von Neumann scheme is formulated, which better handles sparsely sampled data and outperforms current implementations of discrete correlation function methods. This scheme is applied to existing reverberation data of varying quality, and consistency with previously reported time delays is found. In particular, the size-luminosity relation of the broad-line region in quasars is recovered with a scatter comparable to that obtained by other works, yet with fewer assumptions made concerning the process underlying the variability. The proposed method for time-lag determination is particularly relevant for irregularly sampled time series, and in cases where the process underlying the variability cannot be adequately modeled.
27 citations
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...…(5) Denney et al. 2009; (6) Bentz et al. 2009; (7) Stirpe et al. 1994; (8) Denney et al. 2009b (9) Bentz et al. 2006; (10) Denney et al. 2006; (11) Santos-Lleó et al. 2001; (12) Peterson et al. 2002; (13) Dietrich et al. 1998; (14) Peterson et al. 2014. the extrinsic (i.e., multi-object) one....
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TL;DR: In this paper, the authors investigated how the shortening of the time lags correlate with the single-epoch spectral properties and to understand what is the origin of the shortened lags, and they found that the flux ratio between Fe II and H$\beta$ emission lines shows the most prominent correlation, thus confirm that accretion rate is the main driver for the shortened Lags.
Abstract: The radius-luminosity (R-L) relationship of active galactic nuclei (AGNs) established by the reverberation mapping (RM) observations has been widely used as a single-epoch black hole mass estimator in the research of large AGN samples. However, the recent RM campaigns discovered that the AGNs with high accretion rates show shorter time lags by factors of a few comparing with the predictions from the R-L relationship. The explanation of the shortened time lags has not been finalized yet. We collect 8 different single-epoch spectral properties to investigate how the shortening of the time lags correlate with those properties and to understand what is the origin of the shortened lags. We find that the flux ratio between Fe II and H$\beta$ emission lines shows the most prominent correlation, thus confirm that accretion rate is the main driver for the shortened lags. In addition, we establish a new scaling relation including the relative strength of Fe II emission. This new scaling relation can provide less biased estimates of the black hole mass and accretion rate from the single-epoch spectra of AGNs.
26 citations
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...…(25) Jones et al. (2009), (26) Bentz et al. (2016a), (27) Kollatschny & Zetzl (2011), (28) Moustakas, & Kennicutt (2006), (29) Bentz et al. (2006), (30) Zhang et al. (2019), (31) Barth et al. (2013), (32) Hu et al. (2016), (33) Bentz et al. (2014), (34) Santos-Lleó et al. (2001), (35) Marziani et…...
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...…et al. (2019), (22) Denney et al. (2006), (23) Barth et al. (2013), (24) Bentz et al. (2016b), (25) Hu et al. (2016), (26) Bentz et al. (2014), (27) Santos-Lleó et al. (2001), (28) Peterson et al. (2002), (29) Bentz et al. (2007), (30) Lu et al. (2016), (31) Pei et al. (2017), (32) Dietrich et…...
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University of California, Los Angeles1, Harvard University2, University of Auckland3, University of California, Irvine4, California Polytechnic State University5, Brigham Young University6, University of Utah7, University of California, Riverside8, Goddard Space Flight Center9, University of Maryland, College Park10, University of California, Berkeley11, University of Southampton12, Western Kentucky University13, University of Northern Colorado14, Space Telescope Science Institute15, Texas A&M University16, Seoul National University17
TL;DR: In this article, the authors present models of the H$β$-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN (Active Galactic Nucleus) Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well as the mass of the central supermassive black hole.
Abstract: We present models of the H$\beta$-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN (Active Galactic Nucleus) Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well as the mass of the central supermassive black hole. We find that the BLR is generally a thick disk, viewed close to face-on, with preferential emission back toward the ionizing source. The dynamics in our sample range from near-circular elliptical orbits to inflowing or outflowing trajectories. We measure black hole masses of $\log_{10}(M_{\rm BH}/M_\odot) = 6.48^{+0.21}_{-0.18}$ for PG 1310$-$108, $7.50^{+0.25}_{-0.18}$ for Mrk 50, $7.46^{+0.15}_{-0.21}$ for Mrk 141, $7.58^{+0.08}_{-0.08}$ for Mrk 279, $7.11^{+0.20}_{-0.17}$ for Mrk 1511, $6.65^{+0.27}_{-0.15}$ for NGC 4593, and $6.94^{+0.14}_{-0.14}$ for Zw 229$-$015. We use these black hole mass measurements along with cross-correlation time lags and line widths to recover the scale factor $f$ used in traditional reverberation mapping measurements. Combining our results with other studies that use this modeling technique, bringing our sample size to 16, we calculate a scale factor that can be used for measuring black hole masses in other reverberation mapping campaigns. When using the root-mean-square (rms) spectrum and using the line dispersion to measure the line width, we find $\log_{10}(f_{{\rm rms},\sigma})_{\rm pred} = 0.57 \pm 0.19$. Finally, we search for correlations between $f$ and other AGN and BLR parameters and find marginal evidence that $f$ is correlated with $M_{\rm BH}$ and the BLR inclination angle, but no significant evidence of a correlation with the AGN luminosity or Eddington ratio.
24 citations
References
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TL;DR: In this article, a method for measuring correlation functions without interpolating in the temporal domain is proposed which provides an assumption-free representation of the correlation measured in the data and allows meaningful error estimates.
Abstract: A method for measuring correlation functions without interpolating in the temporal domain is proposed which provides an assumption-free representation of the correlation measured in the data and allows meaningful error estimates. Physical interpretation of the cross-correlation function of two series believed to be related by a convolution is shown to require knowledge of the input function's fluctuation power spectrum. Application of the method to two systems reveals no correlation for the optical data of Akn 120, but a strong correlation for the UV data of NGC 4151, placing bounds of between 1.2 and 20 light days on the size of the line-emitting region.
1,139 citations
TL;DR: In this paper, a procedure is described for analyzing a time series of measurements of both the continuum and the emission lines, and it is shown that if the emission line region has a high degree of symmetry, then it is possible to invert the time-dependent line profiles and obtain the phase space distribution of the emission-line gas.
Abstract: Variations in the strengths of the central photoionization source in a quasar or Seyfert galaxy will generate variations in the strengths and profiles of the emission lines. These ''reverberations'' in the emission lines will lag behind the continuum variations due to light travel time effects. A procedure is described for analyzing a time series of measurements of both the continuum and the lines. This procedure permits direct verification of the assumed causal connection of the lines to the continuum. We demonstrate that if the emission line region has a high degree of symmetry, then it is possible to invert the time-dependent line profiles and obtain the phase space distribution of the emission-line gas: i.e., its emissivity and the moments of its velocity distributions as functions of position. The cases of spherical and disk symmetry are considered in detail; the case of a straight jet, which may be relevent to correlated optical and radio variations, is discussed briefly. Explicit calculations of expected line variations have been carried out for several simple models. We suggest that with recently developed instrumentation it should now be possible to apply this technique to Seyfert galaxies. Long term, highly accurate observations will be required for themore » application to quasars.« less
1,034 citations
"Monitoring of the optical and 2.5-1..." refers methods in this paper
...Reverberation-mapping techniques (Blandford & McKee 1982) have been used extensively to map the BLR in several AGN, on scales of light days to light months, notably by the International AGN Watch1 consortium (Alloin et al. 1994)....
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01 Jun 1988
TL;DR: It is shown that physical interpretation of active galactic nuclei cross-correlation functions requires knowledge of the input function's fluctuation power spectrum, involves model-dependence in the form of symmetry assumptions, and must take into account intrinsic scale bias.
Abstract: A method of measuring correlation functions without interpolating in the temporal domain, the discrete correlation function, is introduced. It provides an assumption-free representation of the correlation measured in the data, and allows meaningful error estimates. This method does not produce spurious correlations at zero lag due to correlated errors. It is shown that physical interpretation of active galactic nuclei cross-correlation functions requires knowledge of the input function's fluctuation power spectrum, involves model-dependence in the form of symmetry assumptions, and must take into account intrinsic scale bias. This technique was used to find a correlation in published IUE data for NGC 4151, which indicates that the broad C IV feature emanates from a shell 15 to 75 light-days in radius, assuming spherical symmetry.
818 citations
"Monitoring of the optical and 2.5-1..." refers methods in this paper
...We used both the interpolation method of Gaskell & Sparke (1986) and the discretecorrelation function (DCF) method of Edelson & Krolik (1988), in both cases employing the specific implementation described by White & Peterson (1994)....
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TL;DR: In this article, the authors show that most of the bright quasars from the Palomar-Green (PG) survey appear to emit the bulk of their luminosity (typically more than 90%) between 3 nm and 300 μm (10.7-10^(18) Hz).
Abstract: Continuum observations from ~0.3 nm to 6 cm (10^(9.7)-10^(18) Hz) are presented for 109 bright quasars from the Palomar-Green (PG) survey. Two-thirds of the quasars have been detected in the infrared at wavelengths
between 10 and 100 μm. All of the PG quasars appear to emit the bulk of their luminosity (typically more than 90%) between 3 nm and 300 μm (10^(12)-10^(17) Hz). The total luminosity at wavelengths longer than 1 μm is typically 20%-40% of that at wavelengths shortward of 1 μm. The gross shape of the energy distributions between 3 nm and 300 μm is remarkably similar for all the quasars except the flat-spectrum radio-loud quasars like 3C 273 and can plausibly be fitted by two broad components of thermal emission. In this interpretation the emission in the spectral range ~ 10 nm to 0.3 μm, the "big blue bump," is dominated by 10,00-100,000 K thermal emission from an accretion disk. The emission between 2 μm and 1 mm, the "infrared bump," is made up of reradiation from dust in a distorted disk extending from 0.1 pc to more than 1 kpc. The fairly small range in the relative sizes of the bumps suggests that the covering factor in most of the PG quasars is similar. There is no obvious connection between the strengths of the blue and infrared peaks and whether or not the quasar is radio quiet or radio loud. The mass
of infrared emitting dust is estimated to be ~0.01 M_☉ at 2 μm and ~ 10^5 M_☉ at 60 μm. The radiation from 0.5 μm is thermal emission from the portion of the disk between 0.1 and 1 pc, illuminated primarily by the clouds of the broad-line region. The radiation from 5 μm to 1 mm is reradiation from a warped disk at distances greater than 1 pc from the central source, which is heated directly by radiation from the central source. Optically thin atomic emission (free-free and partially thermalized lines and bound-free) from gas within 1 pc of the central source, whose dust has sublimated, probably contributes to the flux from 0.5 to 2 μm. We believe that there is no convincing evidence for energetically significant nonthermal radiation in the wavelength range 3 nm to 300 μm in the continua of the radio-quiet and steep-spectrum radio-loud PG quasars.
648 citations
"Monitoring of the optical and 2.5-1..." refers background in this paper
...The presence of a universal inflection point near 1.2µm in the spectral energy distribution of radio-quiet AGN’s strongly suggests that the bulk of the near IR flux arises from dust thermal emission (e.g., Barvainis 1987; Sanders et al. 1989)....
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TL;DR: In this paper, thermal radiation by dust can reproduce the overall shape of the bump seen in the near-infrared continua of many QSOs and AGN, and a simple model in which dust grains are heated by the primary nuclear optical/ultraviolet continuum produces the required emission at short wavelengths.
Abstract: It is shown here that thermal radiation by dust can reproduce the overall shape of the bump seen in the near-infrared continua of many QSOs and AGN. A simple model in which dust grains are heated by the primary nuclear optical/ultraviolet continuum produces the required emission at short wavelengths. The model naturally explains the onset of the bump at about 2 microns. This wavelength corresponds to the optically thin emission peak for the hottest possible grains, i.e., graphite grains at their evaporation temperature near 1500 K. Emission longward of 2 microns is due to cooler grains farther from the central source. 33 references.
644 citations
"Monitoring of the optical and 2.5-1..." refers background in this paper
...The presence of a universal inflection point near 1.2µm in the spectral energy distribution of radio-quiet AGN’s strongly suggests that the bulk of the near IR flux arises from dust thermal emission (e.g., Barvainis 1987; Sanders et al. 1989)....
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