Physical Sciences and Mathematics Commons^™

Temporal And Spectral Analysis Of 1es 2344+514 In Two Flaring States Observed By Veritas, Connor Poggemann

Physics

VERITAS observed the bright blazar 1ES 2344+514 during two flaring periods, one from Dec. 17 to Dec. 18, 2015 (MJD 57373-57374) with a peak flux of ~60% of the Crab and another from Nov. 28 to Dec. 3, 2021 (MJD 59546-59551) with a peak flux of ~20% of the Crab. This blazar, located at a redshift of z = 0.044, is classified as an extreme high-frequency-peaked BL Lacertae object (HBL). It is known to be variable, including several previous day-scale flares: Whipple on Dec. 20, 1995, VERITAS on Dec. 7, 2007, and MAGIC on Aug. 11, 2016. The VERITAS near-nightly …

Variability Of Active Galactic Nuclei From Differential Photometry, Nicholas Steven Yee

Physics

The Seoul AGN Monitoring Project, or SAMP for short, is an international project (PI Jonghak Woo from Korea) with the goal of measuring the masses of black holes residing in the center of massive active galactic nuclei (AGNs). AGNs are some of the brightest objects in the universe. Their light is attributed to the accretion of material onto the black hole. However, these objects are too distant to spatially resolve the gravitational sphere of influence of the black hole directly. Instead, we use a technique called reverberation mapping which observes the variability of the AGN power-law continuum emission and the …

Formation Pathways In Brightest Cluster Galaxies: Measuring The Distribution Of Ages, Metallicities, And Hydrodynamics Of Stellar Populations, Priscilla E. Holguin West

Physics

Brightest Cluster Galaxies (BCGs) are the most massive galaxies in the local universe and have had the full age of the universe to build. This makes their formation and evolution history particularly interesting as they offer a glimpse at potential evolutionary pathways for younger systems. We present the radial profile of ages, metallicities, and preliminary classification of companions to 23 BCGs observed using the SparsePak instrument on WIYN by running the STARLIGHT stellar population synthesis models. This analysis of the BCGs’ stellar populations is done by separating each BCG into different regions, and preliminary results of the stellar populations for …

Host-Galaxy Morphology Of 14 Local Active Galaxies As Imaged By The Hubble Space Telescope, Tomas Henry Snyder

Physics

Active galactic nuclei (AGNs) are galaxies with super-massive black holes, that are undergoing accretion, at their centers. The study of these objects provides us with a deeper understanding of how the black holes evolved along with their host galaxies since black hole mass is highly correlated with bulge mass. A sample of 66 AGNs were imaged using the Hubble Space Telescope (HST) and 14 of those are analyzed in this paper to determine their structure, bulge luminosity, and bulge type. The program GALFIT is implemented to determine these parameters, that will be used in further research in the future. These …

Brightest Cluster Galaxy Evolution Exploration: Comparing The Separation Of Cluster X-Ray Light And Visible Wavelength Galaxy Light With Spectral Data, Matthew Aaron Salinas

Physics

Brightest Cluster Galaxies (BCGs), the brightest galaxy in a cluster of hundreds to thousands of galaxies, are some of the biggest, brightest, and most massive galaxies in the universe. Characterizing a BCG can help discover more about galaxy evolution - the aging, changing, and possible merging (collisions) of galaxies. This project involves determining the separation of the peak of x-ray emission of the galaxy cluster, and the peak of visible emission of the BCG to characterize the system as being disturbed or undisturbed that can then lead to discoveries about its formation and evolution. We have found that 17.4% of …

Differential Photometry Of Active Galactic Nuclei Using Time Resolved Observations With The 1m Nickel Telescope Of Lick Observatory, Chance L. Spencer

Physics

Active galactic nuclei (AGNs) are exotic objects in the center of some galaxies with luminosities that can greatly outshine the stars of the host galaxy across the entire electromagnetic spectrum. The origin of the UV/optical light is thought to be due to accretion of material onto the supermassive black hole in their centers. Since these objects are too far away to resolve the gravitational sphere of influence of the black hole directly, we make use of a method called reverberation mapping. We measure the lag between the AGN power-law continuum emitted by the accretion disk and the Doppler-broadened emission lines …

Studying The Potential Of The [Oii] Emission Line As A Surrogate For Stellar Velocity Dispersion In Active Galactic Nuclei, Edward F. Donohue

Physics

We study the emission profiles of 80 active galaxies to find a surrogate for stellar velocity dispersion. We focus on the width of the emission line of once ionized oxygen, [OII], and compare our results to previous work that used [OIII]. In previous research, [OIII] was found to be a good candidate for a surrogate for stellar velocity dispersion, but analysis of the line was complicated by the presence of wings caused by gas infall and outflow in the region. Emission lines with lower ionization levels, like [OII], are known to have less artificial line-broadening from wings. The study of …

Probing The Black-Hole-Mass-Galaxy Connection Of Active Galaxies Using 2d Galaxy Fitting Techniques On Near-Infrared Images, Isak Dan Stomberg

Physics

Active Galactic Nuclei (AGNs) provide a unique opportunity to measure the mass of supermassive black holes located in the centers of their host galaxies. This enables studying the scaling relations between the mass of the black hole and the properties of the host galaxy.

In this thesis, we present an investigation of the relationship between black hole masses and the host galaxy bulge and total luminosity for a pilot sample of 15 objects imaged in the near-infrared with the 8m telescope of Gemini North observatory. We perform a 2D decomposition of the host galaxies using the software Galfit and obtain …

Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line

Physics

Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis.

To probe the accuracy of the fitting process, artificial spectra were created and fitted to …

Determining The Relationship Between The [Oiii] 5007 Å Emission Line Profile And The Stellar Velocity Dispersion In Active Galaxies, Nathaniel Milgram

Physics

The empirical relation between the stellar velocity dispersion (SVD) of the bulge and the mass of the central supermassive black hole (BH) suggests a link between host galaxy and BH evolution. For active galactic nuclei (AGNs), the BH mass (MBH) can be estimated in a straightforward way from the Doppler broadening of the broad emission lines using the so-called virial method. However, the powerful AGN continuum emission often outshines the underlying stellar absorption lines, making it difficult to measure SVD of the host galaxy. Thus, the MBH - SVD relation is difficult to establish for galaxies containing AGNs. As a …

Evidence Of Attenuation Of Vhe Blazar Spectra By Extragalactic Background Light, Cameron Allen

Physics

The spectrum of two blazar objects, 1ES 1959+650 and 1ES 2344+514, are analyzed for evidence of interactions with the Extragalactic Background Light (EBL), using combined data from the Very Energetic Radiation Imaging Telescope Array System and the Fermi Gamma-ray Space Telescope, By analyzing the distinct curvature across the combined spectrum, we infer that the very-high energy (VHE) gamma-rays must be attenuated by interactions with the EBL. We also find that the measured 1ES 1959+650 spectrum is sensitive to the intrinsic blazar model, with a preference for a power-law with an exponential cutoff (EPWL). The measured curvature is a combination of …

Time Variation Of The Broad Hβ And Hα Emission Lines In Active Galactic Nuclei, Bryan R. Scott

Physics

High-quality Keck/LRIS long-slit spectra for a sample of 97 active galaxies selected from the Sloan Digital Sky Survey (redshift between 0.02 & 0.1; Black Hole Mass approximately 10⁷ Solar Masses) were obtained between January 2009 and March 2010 in order to study the black hole (BH) mass scaling relation in the local universe. Typically, the width of the broad Hβ emission line is used to measure the mass of the black hole (MBH). However, signs of variability in the emission line profile are seen for eight objects: While broad Hβ emission lines had previously been observed in spectra from …

Determining The Location Of The Coronal Line Region Within Local Active Galactic Nuclei Using [Fe Vii] Emission Line Properties, Charles Grant Showley

Physics

Given a sample of 99 local AGNs, we study the characteristics of the forbidden [Fe VII] coronal line for the purpose of determining the location of the coronal line region (CLR) within the AGN. We calculate the velocity of the clouds emitting [Fe VII] using the width of the [Fe VII] emission lines compared to [O II] emission lines to establish whether the clouds are inflowing or outflowing. We plot the [Fe VII] and [O II] flux ratios against the AGNs' known black hole masses and stellar velocity dispersions in order to see if there are any correlations between them. …

Modeling The Spectral Energy Distribution Of Mrk 421, Randall L. Oglesby

Physics

Blazars are astronomical objects thought to be powered by the release of gravitational energy by accretion of material into a supermassive black hole located in the central region of the host galaxy. Some AGN present strong relativistic outflows in the form of jets, with blazars being the particular subset whose jets are aligned with our line of sight. Even though blazars account for only a small fraction of all AGN, they are the dominant class source in the high-energy sky. In this thesis we study the spectral energy distribution of Mrk 421, a prototypical blazar. Using publicly available numerical code …

Variability Studies Of Multi-Wavelength Data From Gamma-Ray Blazars Mrk 421 And Mrk 501, Brandon Becker

Physics

In this thesis we take astronomical multi-wavelength data from nearby blazars Markarian 421 and Markarian 501 and perform computational analysis and correlative studies to determine any possible time lag across different bands of our targets as well as to measure the statistical significance of this calculated result. The data was taken over the interval of December 2010 to May 2012 from multiple instruments spanning a broad range of wavelengths. We used the Discrete Correlation Function (DCF) to determine the time lag factor across data set pairs, focusing on X-ray and Very-High-Energy (VHE; >100 GeV) data. To establish the significance of …

Orbital Velocities In The Broad Line Region Of Seyfert 1 Galaxies, Rebecca Renee Rosen

Physics

Active galactic nuclei (AGNs) are among the most energetic objects in the Universe and are believed to be powered by supermassive black holes. By studying optical spectra of these AGNs, information can be acquired about the central black hole and its surroundings. Specifically the broad component of the Hβ emission line can be used to find the velocity of gas in the broad line region, a necessary step in determining the mass of the central black hole. In this thesis, I present the results of using a python code to measure the broad component of Hβ in the spectra of …

Analysis Of The 2008 Flare Of Markarian 421 Flare With Veritas, Casey Allard

Physics

A theoretical light curve model is fit to an observed short term flare of Markarian (Mrk) 421 in the very high energy spectrum. The flare is characterized by its measured light curve from the Very Energetic Radiation Imaging telescope Array System (VERITAS). The flare we analyzed occurred in May 2008. We successfully fit a theoretical model to the Mrk 421 data light curve. The data appears to agree with the Wagner [1] and Salvati [2] models. These models appear to fit both broad and sharp flaring regions found in the measured light curve. Furthermore the Wagner model is used to …