Michael Eracleous
A5040331573- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Scientific Measurement and Uncertainty Evaluation
- Relativity and Gravitational Theory
- Mechanics and Biomechanics Studies
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Laser-induced spectroscopy and plasma
- Heat Transfer Mechanisms
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Magnetic confinement fusion research
- CCD and CMOS Imaging Sensors
Pennsylvania State University
2015-2024
Georgia Institute of Technology
2014-2018
University of Washington
2014-2017
Northwestern University
2007-2010
Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna
2010
College of Charleston
2010
Osservatorio astronomico di Bologna
2010
University of Bologna
2010
Pacific States University
1999-2009
Friedrich-Alexander-Universität Erlangen-Nürnberg
2008
(Abridged) We describe here the most ambitious survey currently planned in optical, Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST have unique capability faint time domain. The design is driven four main themes: probing dark energy matter, taking an inventory Solar System, exploring transient optical sky, mapping Milky Way. wide-field ground-based system sited at Cerro Pach\'{o}n northern Chile. telescope 8.4 m...
The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using original SDSS wide-field imager, and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution novel interferometer. All SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all acquired through 2013 July, 12 (DR12) adding July (including included in previous releases), marking end observing. Relative our public...
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of exciting science opportunities next decade. The Large Synoptic Survey Telescope (LSST) have an effective aperture 6.7 meters and imaging camera field view 9.6 deg^2, be devoted ten-year 20,000 deg^2 south +15 deg. Each pointing imaged 2000 times fifteen second exposures six broad from 0.35 1.1 microns, total point-source depth r~27.5. LSST Science Book describes basic...
Abstract The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and Extended Baryon Oscillation Spectroscopic (eBOSS). As well as its program, eBOSS contains two major subprograms: Time Domain (TDSS) SPectroscopic IDentification ERosita Sources (SPIDERS). This paper describes first data release from SDSS-IV,...
The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. Observations be simultaneous with Time Domain (TDSS) designed for variability studies and Identification of eROSITA Sources (SPIDERS) program X-ray sources. eBOSS use four different tracers to measure distance-redshift relation baryon acoustic oscillations (BAO). Using more than 250,000 new, spectroscopically confirmed luminous red...
SDSS J015957.64+003310.5 is an X-ray selected, $z=0.31$ AGN from the Stripe 82X survey that transitioned a Type 1 quasar to 1.9 between 2000 and 2010. This most distant AGN, first quasar, yet observed have undergone such dramatic change. We re-observed source with double spectrograph on Palomar 5m telescope in July 2014 found spectrum unchanged since From fitting optical spectra, we find flux dropped by factor of 6 2010 while broad H$\alpha$ emission faded broadened. Serendipitous...
SDSS-V will be an all-sky, multi-epoch spectroscopic survey of over six million objects. It is designed to decode the history Milky Way, trace emergence chemical elements, reveal inner workings stars, and investigate origin planets. also create integral-field map gas in Galaxy Local Group that 1,000x larger than current state art at high enough spatial resolution self-regulation mechanisms galactic ecosystems. pioneer systematic, monitoring across whole sky, revealing changes on timescales...
Abstract “Changing-look active galactic nuclei” (CL AGN) show dramatic, rapid changes in optical/UV continuum and broad-line emission. The majority of CL AGN have been found dimming as “turn-off” because most selection methods start from samples spectroscopically confirmed quasars. We present here a sample 82 “turn-on” AGN, 70 which are newly identified. turn-on selected classified galaxies with subsequent significant dramatic variability both the optical mid-infrared bands, indicating...
view Abstract Citations (392) References (108) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Double-peaked Emission Lines in Active Galactic Nuclei Eracleous, Michael ; Halpern, Jules P. We present the results of a comprehensive study broad Hα emission lines radio galaxies and radio-loud quasars. The data consist 74 new spectra plus information drawn from 20 literature. principal result is discovery eight double- peaked profiles that can be fitted by simple...
We report the completion of a survey radio-loud active galactic nuclei (AGNs) begun in an earlier paper with main goal finding and studying broad, double-peaked Balmer lines. present Hα spectra 13 more broad-lined objects, including three profiles. The final sample includes 106 AGNs. In our census 20% objects have lines double peaks or twin shoulders (the "double-peaked emitters"), these 60% disklike emitters) can be fitted quite well model attributing emission to circular, relativistic,...
In recent years, luminous X-ray outbursts with variability amplitudes as high ~ 400 have been serendipitously detected from a small number of active and inactive galaxies. These may result the tidal disruptions stars by supermassive black holes well accretion-disk instabilities. order to place first reliable constraints on rate such in Universe test stellar disruption hypothesis, we performed systematic complete survey for them cross-correlating ROSAT All-Sky Survey (RASS) pointed PSPC data....
We present a uniform and systematic analysis of the 0.6-10 keV X-ray spectra radio-loud active galactic nuclei (AGNs) observed by ASCA. The sample, which is not statistically complete, includes 10 broad-line radio galaxies (BLRGs), five quasars (QSRs), nine narrow-line (NLRGs), (RGs) mixed FR I II types. For several sources ASCA data are presented here for first time. exposure times observations fluxes objects vary over wide range; as result, so does signal-to-noise ratio individual spectra....
A dormant supermassive black hole lurking in the center of a galaxy will be revealed when star passes close enough to torn apart by tidal forces, and flare electromagnetic radiation is emitted bound fraction stellar debris falls back onto accreted. Although disruption rare event galaxy, ≈10−4 yr−1, observational candidates have emerged all-sky X-ray deep ultraviolet (UV) surveys form luminous UV/X-ray flares from otherwise quiescent galaxies. Here we present third candidate discovered Galaxy...
We report the discovery of a new 'changing-look' quasar, SDSS J101152.98+544206.4, through repeat spectroscopy from Time Domain Spectroscopic Survey. This is an addition to small but growing set quasars whose blue continua and broad optical emission lines have been observed decline by large factor on time-scale approximately decade. The 5100 Å monochromatic continuum luminosity this quasar drops >9.8 in rest-frame time interval <9.7 yr, while Hα 55 same amount time. width line increases dim...
Abstract Active galactic nuclei (AGNs) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as changing-look AGN, or at higher luminosities, quasars (CLQs). These surprisingly large sometimes rapid transitions challenge accepted models of quasar physics duty cycles, offer several new avenues for study host galaxies, open a wider interpretation the cause differences between narrow-line AGN. To better characterize extreme...
Using a distance-limited portion of the Sloan Digital Sky Survey (SDSS) Data Release 7, we have identified 28 active galactic nuclei (AGNs) in nearby (d < 80 Mpc) low-mass, low-luminosity dwarf galaxies. The accreting objects at galaxy centers are expected to be intermediate-mass black holes (IMBHs) with M_BH 1e6 M_sun. AGNs were selected using several optical emission-line diagnostics after careful modeling continuum present spectra. We limited our survey spectral characteristics similar...
[ABRIDGED] We have carried out a systematic search for close supermassive black hole binaries among z < 0.7 SDSS quasars Such are predicted by models of and host galaxy co-evolution, therefore their census population properties constitute an important test these models. used automatic technique based on spectroscopic principal component analysis to broad H-beta lines that displaced from the rest-frame quasar more than 1,000 km/s This method can also yield candidates rapidly recoiling holes....
We perform an exploratory study of the physical properties accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modeling spectral energy distributions (SEDs) 12 LLAGNs low-ionization nuclear emission-line regions (LINERs). These SEDs we constructed from high-resolution radio, X-ray optical/UV observations immediate vicinity black hole. adopt a coupled accretion-jet model comprising inner advection-dominated flow (ADAF) outer standard thin disk. present best-fit...
The first terrestrial gravitational wave interferometers have dramatically underscored the scientific value of observing Universe through an entirely different window, and folding this new channel information with traditional astronomical data for a multimessenger view. Laser Interferometer Space Antenna (LISA) will broaden reach astronomy by conducting survey millihertz sky, detecting tens thousands individual astrophysical sources ranging from white-dwarf binaries in our own galaxy to...
Abstract Despite their factor of ∼10 8 difference in black hole mass, several lines evidence suggest possible similarities between accretion flows active galactic nuclei (AGN) and Galactic X-ray binaries. However, it is still unclear whether the geometry disk–corona system binaries directly scales up to AGN this analogy holds different states. We test AGN/X-ray binary by comparing observed correlations UV–to–X-ray spectral index ( α OX ) Eddington ratio those predicted from observations...
We present the first results from an optical reverberation mapping campaign executed in 2014, targeting active galactic nuclei (AGN) MCG+08-11-011, NGC 2617, 4051, 3C 382, and Mrk 374. Our targets have diverse interesting observational properties, including a "changing look" AGN broad-line radio galaxy. Based on continuum-H$\beta$ lags, we measure black hole masses for all five targets. also obtain H$\gamma$ He{\sc ii}\,$\lambda 4686$ lags objects except 382. The indicate radial...
Abstract Active galactic nuclei (AGN) can vary significantly in their rest-frame optical/UV continuum emission, and with strong associated changes broad line on much shorter timescales than predicted by standard models of accretion disks around supermassive black holes. Most such changing-look or changing-state AGN—and at higher luminosities, quasars (CLQs)—have been found via spectroscopic follow-up known showing photometric variability. The Time Domain Spectroscopic Survey the Sloan...
Abstract “Changing-look” active galactic nuclei (CL-AGNs) challenge our basic ideas about the physics of accretion flows and circumnuclear gas around supermassive black holes. Using first-year Sloan Digital Sky Survey V (SDSS-V) repeated spectroscopy nearly 29,000 previously known (AGNs), combined with dedicated follow-up spectroscopy, publicly available optical light curves, we have identified 116 CL-AGNs where (at least) one broad emission line has essentially (dis-)appeared, as well 88...
view Abstract Citations (197) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Elliptical Accretion Disks in Active Galactic Nuclei Eracleous, Michael ; Livio, Mario Halpern, Jules P. Storchi-Bergmann, Thaisa We present a calculation of the profiles emission lines originating relativistic, eccentric disk, and show examples resulting model profiles. Our calculations are motivated by fact that about one-quarter double-peaked observed radio-loud...