A5071476055- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Mechanics and Biomechanics Studies
- Plant Water Relations and Carbon Dynamics
- Pulsars and Gravitational Waves Research
- Statistics Education and Methodologies
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Atmospheric and Environmental Gas Dynamics
- Computational Physics and Python Applications
- Astrophysics and Star Formation Studies
Center for Astrophysics Harvard & Smithsonian
2023-2024
University of Wyoming
2016-2023
We have started a long-term reverberation mapping project using the Wyoming Infrared Observatory 2.3 meter telescope titled "Monitoring AGNs with H\beta\ Asymmetry" (MAHA). The motivations of are to explore geometry and kinematics gas responsible for complex emission-line profiles, ideally leading an understanding structures origins broad-line region (BLR). Furthermore, such provides opportunity search evidence close binary supermassive black holes. describe MAHA report initial results from...
In this third paper of the series reporting on reverberation mapping (RM) campaign active galactic nuclei with asymmetric H$\beta$ emission-line profiles, we present results for 15 Palomar-Green (PG) quasars using spectra obtained between end 2016 to May 2021. This combines long time spans relatively high cadence. For 8 objects, both lags from entire light curves and measurements individual observing seasons are provided. Reverberation 9 our targets has been attempted first time, while 6...
We report the results of long-term reverberation mapping (RM) campaigns nearby active galactic nuclei (AGN) NGC 4151, spanning from 1994 to 2022, based on archived observations FAST Spectrograph Publicly Archived Programs and our new with 2.3m telescope at Wyoming Infrared Observatory. reduce calibrate all spectra in a consistent way, derive light curves broad H$\beta$ line 5100\,{\AA} continuum. Continuum are also constructed using public archival photometric data increase sampling...
The most rapidly evolving regions of galaxies often display complex optical spectra with emission lines excited by massive stars, shocks and accretion on to supermassive black holes. Standard calibrations (such as for the star formation rate) cannot be applied such mixed spectra. In this paper, we isolate contributions formation, shock excitation active galactic nucleus (AGN) activity line luminosities individual spatially resolved across central 3 × kpc2 region barred spiral galaxy NGC 613....
Abstract We report first-time reverberation-mapping results for 14 active galactic nuclei (AGNs) from the ongoing Monitoring AGNs with H β Asymmetry campaign (MAHA). These utilize optical spectra obtained Long Slit Spectrograph on Wyoming Infrared 2.3 m Telescope between 2017 November and 2023 May. MAHA combines long-duration monitoring high cadence. multiple observing seasons nine of objects. include time lags, supermassive black hole masses, velocity-resolved lags. The lags allow us to...
We present the results of photometric and spectroscopic monitoring campaigns changing look AGN NGC 3516 carried out in 2018 to 2020 covering wavelength range from X-ray optical. The facilities included telescopes CMO SAI MSU, 2.3-m WIRO telescope, XRT UVOT Swift. found that brightened a high state could be classified as Sy1.5 during late spring 2020. have measured time delays responses Balmer He II 4686 lines continuum variations. In case best-characterized broad H-beta line, delay...
We report the results of reverberation mapping three bright Seyfert galaxies, Mrk 79, NGC 3227, and 841, from a campaign conducted December 2016 to May 2017 with Wyoming Infrared Observatory (WIRO) 2.3-meter telescope. All these targets have shown asymmetric broad H$\beta$ emission lines in past, although their were relatively symmetric during our observations. measured H\beta\ time lags for all estimated masses black holes -- first case 841. For 79 data are sufficient quality resolve...
ABSTRACT We present the results of photometric and spectroscopic monitoring campaigns changing look AGN NGC 2617 carried out from 2016 until 2022 covering wavelength range X-ray to near-IR. The facilities included telescopes SAI MSU, MASTER Global Robotic Net, 2.3-m WIRO telescope, Swift, others. found significant variability at all wavelengths and, specifically, in intensities profiles broad Balmer lines. measured time delays ∼6 d (∼8 d) responses Hβ (Hα) line continuum variations....
ABSTRACT X-ray properties of active galactic nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some largest known rates without high-quality data. obtained new Chandra ACIS-S observations and nearly simultaneous optical spectrophotometry to investigate these extreme super-Eddington accreting massive black holes (SEAMBHs). combined our measurements those other AGNs, which have best-determined...
Determining black hole masses and accretion rates with better accuracy precision is crucial for understanding quasars as a population. These are fundamental physical properties that underpin models of active galactic nuclei. A primary technique to measure the mass employs reverberation mapping low-redshift quasars, which then extended via radius-luminosity relationship broad-line region estimate based on single-epoch spectra. An updated incorporates flux ratio optical Fe ii H$\beta$ ($\equiv...
Abstract Weak emission-line quasars (WLQs) are a subset of type 1 that exhibit extremely weak Ly α + N v λ 1240 and/or C iv 1549 emission lines. We investigate the relationship between properties and accretion rate for sample 230 “ordinary” 18 WLQs at z < 0.5 1.5 3.5 have rest-frame ultraviolet optical spectral measurements. apply correction to H β -based black hole mass ( M BH ) estimates these using strength Fe ii emission. confirm previous findings WLQs’ values overestimated by up an...
The spectrum of a quasar contains important information about its properties. Thus, it can be expected that two quasars with similar spectra will have properties, but just how has not before been quantified. Here we compare the ultraviolet sample 5553 from Data Release 7 Sloan Digital Sky Survey, focusing on 1350 Å ≤λ ≤ 2900 rest-frame region which prominent emission lines Si iv, O iv], C iii], and Mg ii species. We use principal component analysis to determine dominant components spectral...
The X-ray properties of Active Galactic Nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some largest known rates without high-quality data. obtained new Chandra ACIS-S observations and nearly simultaneous optical spectrophotometry to investigate these extreme super-Eddington accreting black holes (SEAMBHs). combined our measurements those other AGNs, which have best-determined masses rates....
We report first-time reverberation mapping results for 14 AGNs from the ongoing Monitoring with H$\beta$ Asymmetry campaign (MAHA). These utilize optical spectra obtained Long Slit Spectrograph on Wyoming Infrared 2.3m Telescope between 2017 November-2023 May. MAHA combines long-duration monitoring high cadence. multiple observing seasons 9 of objects. include time lags, supermassive black hole masses, and velocity-resolved lags. The lags allow us to investigate kinematics broad-line region.
Radio core dominance measurements, an indicator of jet orientation, sometimes rely on flux density measurements from large-area surveys like Faint Images the Sky at Twenty cm (FIRST) that have angular resolution only 5''. Such low-resolution often fail to resolve cores extended emission, resulting in erroneous measurement. We focus investigating this effect for a sample 119 radio-loud quasars. obtained continuum observations NSF's Karl G. Jansky Very Large Array (VLA) 10 GHz A configuration...
Abstract Quasar black hole masses are most commonly estimated using broad emission lines in single epoch spectra based on scaling relationships determined from reverberation mapping of small samples low-redshift objects. Several effects have been identified requiring modifications to these relationships, resulting significant reductions the mass determinations at high redshift. Correcting systematic biases is critical understanding among and host galaxy properties. We completing a program...
In this third paper of the series reporting on reverberation mapping (RM) campaign active galactic nuclei with asymmetric H$β$ emission-line profiles, we present results for 15 Palomar-Green (PG) quasars using spectra obtained between end 2016 to May 2021. This combines long time spans relatively high cadence. For 8 objects, both lags from entire light curves and measurements individual observing seasons are provided. Reverberation 9 our targets has been attempted first time, while 6 others...
We report the results of long-term reverberation mapping (RM) campaigns nearby active galactic nuclei (AGN) NGC 4151, spanning from 1994 to 2022, based on archived observations FAST Spectrograph Publicly Archived Programs and our new with 2.3m telescope at Wyoming Infrared Observatory. reduce calibrate all spectra in a consistent way, derive light curves broad H$β$ line 5100\,Å continuum. Continuum are also constructed using public archival photometric data increase sampling cadences....
Weak emission-line quasars (WLQs) are a subset of Type 1 that exhibit extremely weak Ly$α+$N V $λ$1240 and/or C IV $λ$1549 emission lines. We investigate the relationship between properties and accretion rate for sample 230 `ordinary' 18 WLQs at $z < 0.5$ $1.5 z 3.5$ have rest-frame ultraviolet optical spectral measurements. apply correction to H$β$-based black-hole mass ($M_{\rm BH}$) estimates these using strength Fe II emission. confirm previous findings WLQs' $M_{\rm BH}$ values...
We present the results of photometric and spectroscopic monitoring campaigns changing look AGN NGC~2617 carried out from 2016 until 2022 covering wavelength range X-ray to near-IR. The facilities included telescopes SAI MSU, MASTER Global Robotic Net, 2.3-m WIRO telescope, Swift, others. found significant variability at all wavelengths and, specifically, in intensities profiles broad Balmer lines. measured time delays ~ 6 days (~ 8 days) responses H-beta (H-alpha) line continuum variations....