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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TL;DR: In this article, a reanalysis of broad emission-line reverberation-mapping data was carried out for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis, and it was shown that the highest precision measure of the virial product cτΔV2/G is obtained by using the cross-correlation function centroid (cf.
Abstract: We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data From objects with multiple line measurements, we find that the highest precision measure of the virial product cτΔV2/G, where τ is the emission-line lag relative to continuum variations and ΔV is the emission-line width, is obtained by using the cross-correlation function centroid (as opposed to the cross-correlation function peak) for the time delay and the line dispersion (as opposed to FWHM) for the line width and by measuring the line width in the variable part of the spectrum Accurate line-width measurement depends critically on avoiding contaminating features, in particular the narrow components of the emission lines We find that the precision (or random component of the error) of reverberation-based black hole mass measurements is typically around 30%, comparable to the precision attained in measurement of black hole masses in quiescent galaxies by gas or stellar dynamical methods Based on results presented in a companion paper by Onken et al, we provide a zero-point calibration for the reverberation-based black hole mass scale by using the relationship between black hole mass and host-galaxy bulge velocity dispersion The scatter around this relationship implies that the typical systematic uncertainties in reverberation-based black hole masses are smaller than a factor of 3 We present a preliminary version of a mass-luminosity relationship that is much better defined than any previous attempt Scatter about the mass-luminosity relationship for these AGNs appears to be real and could be correlated with either Eddington ratio or object inclination
1,893 citations
Cites methods from "Monitoring of the optical and 2.5-1..."
...We examined two completely independent sets of data, one from theWise Observatory program in 1988 (Maoz et al. 1990) and one from an International AGN Watch project in 1996 (Santos-Lleó et al. 2001)....
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Georgia State University1, Niels Bohr Institute2, Ohio State University3, University of California, Irvine4, University of Arizona5, California Polytechnic State University6, University of California, Riverside7, University of California, Berkeley8, Princeton University9, University of California, Los Angeles10, California Institute of Technology11, University of California, Santa Barbara12, Seoul National University13
TL;DR: In this article, the authors present an updated and revised analysis of the relationship between the H{beta} broadline region (BLR) radius and the luminosity of the active galactic nucleus (AGN).
Abstract: We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19more » {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.« less
795 citations
TL;DR: In this article, a sample of optical light curves for 100 quasars, 70 of which have black hole mass estimates, was used to estimate the characteristic timescale and amplitude of flux variations; their approach is not affected by biases introduced from discrete sampling effects.
Abstract: We analyze a sample of optical light curves for 100 quasars, 70 of which have black hole mass estimates. Our sample is the largest and broadest used yet for modeling quasar variability. The sources in our sample have z < 2.8, 1042 λL λ(5100 A) 1046, and 106 M BH/M ☉ 1010. We model the light curves as a continuous time stochastic process, providing a natural means of estimating the characteristic timescale and amplitude of quasar variations. We employ a Bayesian approach to estimate the characteristic timescale and amplitude of flux variations; our approach is not affected by biases introduced from discrete sampling effects. We find that the characteristic timescales strongly correlate with black hole mass and luminosity, and are consistent with disk orbital or thermal timescales. In addition, the amplitude of short-timescale variations is significantly anticorrelated with black hole mass and luminosity. We interpret the optical flux fluctuations as resulting from thermal fluctuations that are driven by an underlying stochastic process, such as a turbulent magnetic field. In addition, the intranight variations in optical flux implied by our empirical model are 0.02 mag, consistent with current microvariability observations of radio-quiet quasars. Our stochastic model is therefore able to unify both long- and short-timescale optical variations in radio-quiet quasars as resulting from the same underlying process, while radio-loud quasars have an additional variability component that operates on timescales 1 day.
670 citations
TL;DR: In this paper, the authors presented high-resolution Hubble Space Telescope images of all 35 active galactic nuclei (AGNs) with optical reverberation-mapping results, which they have modeled to create a nucleus-free image of each AGN host galaxy.
Abstract: We present high-resolution Hubble Space Telescope images of all 35 active galactic nuclei (AGNs) with optical reverberation-mapping results, which we have modeled to create a nucleus-free image of each AGN host galaxy. From the nucleus-free images, we determine the host-galaxy contribution to ground-based spectroscopic luminosity measurements at 5100 A. After correcting the luminosities of the AGNs for the contribution from starlight, we re-examine the Hβ R BLR-L relationship. Our best fit for the relationship gives a power-law slope of 0.52 with a range of 0.45-0.59 allowed by the uncertainties. This is consistent with our previous findings, and thus still consistent with the naive assumption that all AGNs are simply luminosity-scaled versions of each other. We discuss various consistency checks relating to the galaxy modeling and starlight contributions, as well as possible systematic errors in the current set of reverberation measurements from which we determine the form of the R BLR-L relationship.
646 citations
Cites result from "Monitoring of the optical and 2.5-1..."
...We include here only the results for Mrk 279 reported by Santos-Lleó et al. (2001)....
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TL;DR: In this article, the authors measured the host-galaxy starlight contribution to the continuum luminosity at 5100? through the typical ground-based slit position and geometry used in the reverberation-mapping campaigns.
Abstract: We have obtained high-resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGNs) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure the host-galaxy starlight contribution to the continuum luminosity at 5100 ? through the typical ground-based slit position and geometry used in the reverberation-mapping campaigns. We find that removing the starlight contribution results in a significant correction to the luminosity of each AGN both for lower luminosity sources, as expected, but also for the higher luminosity sources such as the PG quasars. After accounting for the host galaxy starlight, we revisit the well-known broad-line region radius-luminosity relationship for nearby AGNs. We find the power-law slope of the relationship for the H? line to be 0.518 ? 0.039, shallower than what was previously reported and consistent with the slope of 0.5 expected from the naive theoretical assumption that all AGNs have, on average, the same ionizing spectrum and the same ionization parameter and gas density in the H? line-emitting region.
476 citations
References
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Ohio State University1, University of California, Berkeley2, Harvard University3, Lowell Observatory4, Sternberg Astronomical Institute5, Russian Academy of Sciences6, University of Science and Technology of China7, University of Hertfordshire8, Tel Aviv University9, University of California, Los Angeles10, Isaac Newton Institute11, Katholieke Universiteit Leuven12
TL;DR: In this paper, the results of 3 yr of ground-based observations of the Seyfert 1 galaxy NGC 5548 were combined with previously reported data, yielding optical continuum and broad-line Hβ light curves for a total of 8 yr.
Abstract: We present the results of 3 yr of ground-based observations of the Seyfert 1 galaxy NGC 5548, which, combined with previously reported data, yield optical continuum and broad-line Hβ light curves for a total of 8 yr. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this 8 yr period, the nuclear continuum has varied by more than a factor of 7, and the Hβ emission line has varied by a factor of nearly 6. The Hβ emission line responds to continuum variations with a time delay or lag of ~10-20 days, the precise value varying somewhat from year to year. We find some indications that the lag varies with continuum flux in the sense that the lag is larger when the source is brighter.
94 citations
"Monitoring of the optical and 2.5-1..." refers methods in this paper
...As the measurements made from the spectra are subject to systematic differences between the four data sets used, we applied the prescriptions of Peterson et al. (1999) to intercalibrate the data sets, and correct for aperture effects....
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TL;DR: In this paper, the observed profiles of H I, He I, and He II emission lines in 19 Seyfert 1 galaxies are presented in accurate graphical form for comparison with theoretical models.
Abstract: Observed profiles of H I, He I, and He II emission lines in 19 Seyfert 1 galaxies are presented. The data, reduced to energy units versus radial velocity, are given in accurate graphical form for comparison with theoretical models. The profiles are shown as directly observed and as corrected for the blending effects of other lines. Some implications of these profiles on current models of active galactic nuclei are discussed.
85 citations
"Monitoring of the optical and 2.5-1..." refers background in this paper
...…its celestial position allows an uninterrupted 12-month visibility window for ISO and it has a well-documented variability history in the optical (Osterbrock & Shuder 1982; Peterson et al. 1985; Maoz et al. 1990; Stirpe et al. 1994), the UV 1 For a complete panorama of the AGN Watch data sets,…...
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TL;DR: In this paper, the authors present the extraction and processing of the IUE Low Dispersion spectra within the framework of the ESA Newly Extracted Spectra" (INES) System.
Abstract: We present the extraction and processing of the IUE Low Dispersion spectra within the framework of the ESA \IUE Newly Extracted Spectra" (INES) System. Weak points of SWET, the optimal extraction imple- mentation to produce the NEWSIPS output products (extracted spectra) are discussed, and the procedures im- plemented in INES to solve these problems are outlined. The more relevant modications are: 1) the use of a new noise model, 2) a more accurate representation of the spa- tial prole of the spectrum and 3) a more reliable deter- mination of the background. The INES extraction also includes a correction for the contamination by solar light in long wavelength spectra. Examples showing the im- provements obtained in INES with respect to SWET are described. Finally, the linearity and repeatability charac- teristics of INES data are evaluated and the validity of the errors provided in the extraction is discussed.
74 citations
01 Jan 1994
TL;DR: A discussion on Coordination of Observations at Many Wavelengths was held in this paper, where the present generation of ground-based and large-scale ground-and-space-based telescopes were discussed.
Abstract: Editorial. Part 1: I. Achievements of the Present Generation of Space Observatories. II. Achievements of the Present Generation of Ground--Based Telescopes. III. Stars. IV. Interstellar Medium and Galaxies. V. Cosmology. VI. Observations at Many Wavelengths: Panel Discussion on Coordination of Observations at Many Wavelengths. VII. The New Generation of Large Ground--Based Telescopes. VIII. The New Generation Space Telescopes. IX. New Technologies for Astronomy. X. Summary, Priorities and Objectives for the 21st Century. Part 2: XI. Stars. XII. Interstellar Medium and Galaxies. XIII. New Technologies for Astronomy. Index.
66 citations
TL;DR: In this paper, the results of about 15 years of monitoring of the variable Seyfert 1 galaxy NGC 3783 in the infrared were presented, showing that the spectrum of this galaxy stays constant in shape.
Abstract: The results of about 15 years of monitoring of the variable Seyfert 1 galaxy NGC 3783 in the infrared are presented. The spectrum of the variable component stays constant in shape. Changes in the infrared appear to lag those in the ultraviolet by about 80 to 90 d. Like the other Seyfert 1 galaxies Fairall 9 and NGC 1566, the near-infrared behaviour of NGC 3783 can be modelled by a dust shell at about 1500 K whose heating depends on changes in the UV flux of the central power source
65 citations
"Monitoring of the optical and 2.5-1..." refers background in this paper
...…delay corresponds closely to the lighttravel time to the dust sublimation radius rin; measured values of rin are 400 light days for Fairall 9 (Clavel et al. 1989), 50 light days for NGC 1566 (Baribaud et al. 1992), 80 light days for NGC 3783 (Glass 1992) and 32 light days for Mrk 744 (Nelson 1996)....
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