arXiv subjects

Eric S. Perlman

Publications and source records attributed to Eric S. Perlman.

At least 19 recordsLinked to original sources

arXiv2025

The Impact of Supermassive Black Holes on Exoplanet Habitability. I. Spanning the Natural Mass Range

While the influence of supermassive black hole (SMBH) activity on habitability has garnered attention, the specific effects of active galactic nucleus (AGN) winds, particularly ultrafast outflows (UFOs), on planetary atmospheres remain largely unexplored. This study aims to fill this gap by investigating the relationship between SMBH mass at the galactic center and exoplanetary habitability, given that SMBH masses are empirically confirmed to span approximately 5 orders of magnitude in galaxies. Through simplified models, we account for various results involving the relationships between the distance from the planet to the central SMBH and the mass of the SMBH. Specifically, we show that increased SMBH mass leads to higher atmospheric heating and elevated temperatures, greater molecular thermal velocities, and enhanced mass loss, all of which diminish with distance from the galactic center. Energy-driven winds consistently have a stronger impact than momentum-driven ones. Crucially, ozone depletion is shown to rise with SMBH mass and decrease with distance from the galactic center, with nearly complete ozone loss ($\sim100\%$) occurring across galactic scales for SMBH masses $\geq 10^8 M_\odot$ in the energy-driven case. This study emphasizes that SMBH growth over cosmic time may have produced markedly different impacts on galactic habitability, depending on both the mass of the central black hole (BH) and the location of planetary systems within their host galaxies.

astro-ph.GA↗

arXiv2024

Powerful Radio-Loud Quasars are Triggered by Galaxy Mergers in the Cosmic Bright Ages

While supermassive black holes are ubiquitous features of galactic nuclei, only a small minority are observed during episodes of luminous accretion. The physical mechanism(s) driving the onset of fueling and ignition in these active galactic nuclei (AGN) are still largely unknown for many galaxies and AGN-selection criteria. Attention has focused on AGN triggering by means of major galaxy mergers gravitationally funneling gas towards the galactic center, with evidence both for and against this scenario. However, several recent studies have found that radio-loud AGN overwhelmingly reside in ongoing or recent major galaxy mergers. In this study, we test the hypothesis that major galaxy mergers are important triggers for radio-loud AGN activity in powerful quasars during cosmic noon (1 < z < 2). To this end, we compare Hubble Space Telescope WFC3/IR observations of the z > 1 3CR radio-loud broad-lined quasars to three matched radio-quiet quasar control samples. We find strong evidence for major-merger activity in nearly all radio-loud AGN, in contrast to the much lower merger fraction in the radio-quiet AGN. These results suggest major galaxy mergers are key ingredients to launching powerful radio jets. Given many of our radio-loud quasars are blue, our results present a possible challenge to the "blow-out" paradigm of galaxy evolution models in which blue quasars are the quiescent end result following a period of red quasar feedback initiated by a galaxy merger. Finally, we find a tight correlation between black hole mass and host galaxy luminosity for these different high-redshift AGN samples inconsistent with those observed for local elliptical galaxies.

astro-ph.GA↗

arXiv2022

The JetCurry Code. I. Reconstructing Three-Dimensional Jet Geometry from Two-Dimensional images

We present a reconstruction of jet geometry models using numerical methods based on a Markov ChainMonte Carlo (MCMC) and limited memory Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimized algorithm. Our aim is to model the three-dimensional geometry of an AGN jet using observations, which are inherently two-dimensional. Many AGN jets display complex hotspots and bends over the kiloparsec scales. The structure of these bends in the jets frame may be quite different than what we see in the sky frame, transformed by our particular viewing geometry. The knowledge of the intrinsic structure will be helpful in understanding the appearance of the magnetic field and hence emission and particle acceleration processes over the length of the jet. We present the method used, as well as a case study based on a region of the M87 jet.

astro-ph.IM↗

arXiv2022

$JetCurry$ I. Reconstructing Three-Dimensional Jet Geometry from Two-Dimensional Images

We present a three-dimensional (3-D) visualization of jet geometry using numerical methods based on a Markov Chain Monte Carlo (MCMC) and limited memory Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimized algorithm. Our aim is to visualize the 3-D geometry of an active galactic nucleus (AGN) jet using observations, which are inherently two-dimensional (2-D) images. Many AGN jets display complex structures that include hotspots and bends. The structure of these bends in the jet's frame may appear quite different than what we see in the sky frame, where it is transformed by our particular viewing geometry. The knowledge of the intrinsic structure will be helpful in understanding the appearance of the magnetic field and hence emission and particle acceleration processes over the length of the jet. We present the $JetCurry$ algorithm to visualize the jet's 3-D geometry from its 2-D image. We discuss the underlying geometrical framework and outline the method used to decompose the 2-D image. We report the results of our 3-D visualization of the jet of M87, using the test case of the knot D region. Our 3-D visualization is broadly consistent with the expected double helical magnetic field structure of the knot D region of the jet. We also discuss the next steps in the development of the $JetCurry$ algorithm.

astro-ph.HE↗

arXiv2022

Probing Spacetime Foam with Extragalactic Sources of High-Energy Photons

Quantum fluctuations can endow spacetime with a foamy structure. In this review article we discuss our various proposals to observationally constrain models of spacetime foam. One way is to examine if the light wave-front from a distant quasar or GRB can be noticeably distorted by spacetime-foam-induced phase incoherence. As the phase fluctuations are proportional to the distance to the source, but inversely proportional to the wavelength, ultra-high energy photons ($>1$ TeV) from distant sources are particularly useful. We elaborate on several proposals, including the possibility of detecting spacetime foam by observing "seeing disks" in the images of distant quasars and active galactic nuclei. We also discuss the appropriate distance measure for calculating the expected angular broadening. In addition, we discuss our more recent work in which we investigate whether wave-front distortions on small scales (due to spacetime foam) can cause distant objects become undetectable because the phase fluctuations have accumulated to the point at which image formation is impossible. Another possibility that has recently become accessible is to use interferometers to observe cosmologically distant sources, therefore giving a large baseline perpendicular to the local wave vector over which the wave front could become corrugated and thus distorted, reducing or eliminating its fringe visibility. We argue that all these methods ultimately depend on the availability of ways (if any) to carry out proper averaging of contributions from different light paths from the source to the telescope.

gr-qc↗

arXiv2022

Characteristics of Kepler Eclipsing Binaries Displaying a Significant O'Connell Effect

The O'Connell effect - the presence of unequal maxima in eclipsing binaries - remains an unsolved riddle in the study of close binary systems. The Kepler space telescope produced high precision photometry of nearly 3,000 eclipsing binary systems, providing a unique opportunity to study the O'Connell effect in a large sample and in greater detail than in previous studies. We have characterized the observational properties - including temperature, luminosity, and eclipse depth - of a set of 212 systems (7.3% of Kepler eclipsing binaries) that display a maxima flux difference of at least 1%, representing the largest sample of O'Connell effect systems yet studied. We explored how these characteristics correlate with each other to help understand the O'Connell effect's underlying causes. We also describe some system classes with peculiar light curve features aside from the O'Connell effect (~30% of our sample), including temporal variation and asymmetric minima. We found that the O'Connell effect size's correlations with period and temperature are inconsistent with Kouzuma's starspot study. Up to 20% of systems display the parabolic eclipse timing variation signal expected for binaries undergoing mass transfer. Most systems displaying the O'Connell effect have the brighter maximum following the primary eclipse, suggesting a fundamental link between which maximum is brighter and the O'Connell effect's physical causes. Most importantly, we find that the O'Connell effect occurs exclusively in systems where the components are close enough to significantly affect each other, suggesting that the interaction between the components is ultimately responsible for causing the O'Connell effect.

astro-ph.SR↗

arXiv2021

Lightcurve Evolution of the nearest Tidal Disruption Event: A late-time, radio-only flare

Tidal disruption events (TDEs) occur when a star passes close enough to a galaxy's supermassive black hole to be disrupted by tidal forces. We discuss new observations of IGRJ12580+0134, a TDE observed in NGC 4845 (d=17 Mpc) in November 2010, with the Karl G. Jansky Very Large Array (JVLA). We also discuss a reanalysis of 2010-2011 Swift and XMM-Newton observations, as well as new, late-time Swift observations. Our JVLA observations show a decay of the nuclear radio flux until 2015, when a plateau was seen, and then a significant (~factor 3) radio flare during 2016. The 2016 radio flare was also accompanied by radio spectral changes, but was not seen in the X-rays. We model the flare as resulting from the interaction of the nuclear jet with a cloud in the interstellar medium. This is distinct from late-time X-ray flares in a few other TDEs where changes in the accretion state and/or a fallback event were suggested, neither of which appears possible in this case. Our reanalysis of the Swift and XMM-Newton data from 2011 shows significant evidence for thermal emission from a disk, as well as a very soft power-law. This, in addition to the extreme X-ray flux increase seen in 2010 (a factor of >$100) bolsters the identification of IGRJ12580+0134 as a TDE, not an unusual AGN variability event.

astro-ph.HE↗

arXiv2019

Kiloparsec-scale Jets: Physics, Emission Mechanisms, and Challenges

Jets are a ubiquitous part of the accretion process, created in AGN, by a coupling between the magnetic field near the central black hole and inflowing material. We point out what advances can be achieved by new technologies, concentrating on kiloparsec scales, beyond the Bondi radius, where accretion stops. Here, jets profoundly influence their host galaxy and the surrounding clusters and groups, transporting prodigious amounts of matter and energies to scales of hundreds of kpc. Basic questions still remain regarding jet physics, which new instruments can advance greatly. The ngVLA, LOFAR, JWST and LUVOIR, as well as a Chandra successor, will give higher angular resolution and sensitivity. This will allow us to probe the emission mechanisms and dynamics of jets, and search for links between these areas, magnetic fields, particle acceleration and high-energy emission mechanisms. We stress the need for polarimetry in the X-ray and optical, critical to many of the most important questions in jet physics. We hope to directly probe resolved, flaring components, which for the first time will allow us to reveal how jets respond to stimuli and link statics and dynamics.

astro-ph.GA↗

arXiv2019

Relativistic Jets in the Accretion & Collimation Zone: New Challenges Enabled by New Instruments

Jets are a ubiquitous part of the accretion process, seen in a wide variety of objects ranging from active galaxies (AGN) to X-ray binary stars and even newly formed stars. AGN jets are accelerated by the supermassive black hole of their host galaxy by a coupling between the magnetic field and inflowing material. They are the source for many exciting phenomena and can profoundly influence the larger galaxy and surrounding cluster. This White Paper points out what advances can be achieved in the field by new technologies, concentrating on the zone where jets are accelerated to relativistic speeds and collimated. The ngVLA and new space VLBI missions will give higher angular resolution, sensitivity and fidelity in the radio, penetrating this zone for additional objects and allowing us to resolve fundamental questions over the physics of jet acceleration and collimation. Interferometry in other bands would allow us to probe directly flaring components. We also emphasize the need for polarimetry, which is essential to revealing the role and configuration of magnetic fields.

astro-ph.GA↗

arXiv2017

Compact Resolved Ejecta in the Nearest Tidal Disruption Event

Tidal disruption events (TDEs) occur when a star or sub-stellar object passes close enough to a galaxy's supermassive black hole to be disrupted by tidal forces. NGC 4845 (d=17 Mpc) was host to a TDE, IGR J12580+0134, detected in November 2010. Its proximity offers us a unique close-up of the TDE and its aftermath. We discuss new Very Long Baseline Array (VLBA) and Karl G. Jansky Very Large Array (JVLA) observations, which show that the radio flux from the active nucleus created by the TDE has decayed in a manner consistent with predictions from a jet-circumnuclear medium interaction model. This model explains the source's broadband spectral evolution, which shows a spectral peak that has moved from the submm (at the end of 2010) to GHz radio frequencies (in 2011-2013) to <1 GHz in 2015. The milliarcsecond-scale core is circularly polarized at 1.5 GHz but not at 5 GHz, consistent with the model. The VLBA images show a complex structure at 1.5 GHz that includes an east west extension ~40 milliarcsec (3 pc) long as well as a resolved component 52 milliarcsec (4.1 pc) northwest of the flat-spectrum core, which is all that can be seen at 5 GHz. If ejected in 2010, the NW component must have had v=0.96 c over five years. However, this is unlikely, as our model suggests strong deceleration to speeds < 0.5c within months and a much smaller, sub-parsec size. In this interpretation, the northwest component could have either a non-nuclear origin or be from an earlier event.

astro-ph.HE↗

arXiv2016

Multi-Wavelength Polarimetry and Spectral Study of M87 Jet During 2002-2008

We present a multi-wavelength polarimetric and spectral study of M87 jet obtained at sub- arcsecond resolution between 2002 and 2008. The observations include multi-band archival VLA polarimetry data sets along with the HST imaging polarimetry. These observations have better angular resolution than previous work by factors of 2-3 and in addition, allow us to explore the time domain. These observations envelope the huge flare in HST-1 located at 0."86 from the nucleus (Cheung et al. 2007; Harris et al. 2009; Madrid 2009; Perlman et al. 2011). The increased resolution enables us to view more structure in each knot, showing several resolved sub-components. We also see apparent helical structure in the polarization vectors in several knots, with polarization vectors turning either clockwise or counterclockwise near the flux maxima in various places as well as show filamentary undulations. Some of these characteristics are correlated with flux and polarization maxima while others are not. We also examine the total flux and fractional polarization and look for changes in both radio and optical since the observations of Perlman et al. (1999) and test them against various models based on shocks and instabilities in the jet. Our results are broadly consistent with previous spine-sheath models and recollimation shock models, however, they require additional combinations of features to explain the observed complexity, e.g. shearing of magnetic field lines near the jet surface and compression of the toroidal component near shocks. In particular, in many regions we find apparently helical features both in total flux and polarization. We discuss the physical interpretation of these features.

astro-ph.HE↗

arXiv2016

New constraints on quantum foam models from X-ray and gamma-ray observations of distant quasars

Astronomical observations of distant quasars may be important to test models for quantum gravity, which posit Planck-scale spatial uncertainties ('spacetime foam') that would produce phase fluctuations in the wavefront of radiation emitted by a source, which may accumulate over large path lengths. We show explicitly how wavefront distortions cause the image intensity to decay to the point where distant objects become undetectable if the accumulated path-length fluctuations become comparable to the wavelength of the radiation. We also reassess previous efforts in this area. We use X-ray and gamma-ray observations to rule out several models of spacetime foam, including the interesting random-walk and holographic models.

astro-ph.CO↗

arXiv2016

The Spectacular Radio-Near-IR-X-ray Jet of 3C 111: X-ray Emission Mechanism and Jet Kinematics

Relativistic jets are the most energetic manifestation of the active galactic nucleus (AGN) phenomenon. AGN jets are observed from the radio through gamma-rays and carry copious amounts of matter and energy from the sub-parsec central regions out to the kiloparsec and often megaparsec scale galaxy and cluster environs. While most spatially resolved jets are seen in the radio, an increasing number have been discovered to emit in the optical/near-IR and/or X-ray bands. Here we discuss a spectacular example of this class, the 3C 111 jet, housed in one of the nearest, double-lobed FR II radio galaxies known. We discuss new, deep Chandra and HST observations that reveal both near-IR and X-ray emission from several components of the 3C 111 jet, as well as both the northern and southern hotspots. Important differences are seen between the morphologies in the radio, X-ray and near-IR bands. The long (over 100 kpc on each side), straight nature of this jet makes it an excellent prototype for future, deep observations, as it is one of the longest such features seen in the radio, near-IR/optical and X-ray bands. Several independent lines of evidence, including the X-ray and broadband spectral shape as well as the implied velocity of the approaching hotspot, lead us to strongly disfavor the EC/CMB model and instead favor a two-component synchrotron model to explain the observed X-ray emission for several jet components. Future observations with NuSTAR, HST, and Chandra will allow us to further constrain the emission mechanisms.

astro-ph.GA↗

arXiv2016

The Environment of z >1 3CR Radio Galaxies and QSOs: From Proto-Clusters to Clusters of Galaxies?

We study the cluster environment for a sample of 21 radio loud AGN from the 3CR catalog at z>1, 12 radio galaxies and 9 quasars with HST images in the optical and IR. We use two different approaches to determine cluster candidates. We identify the early type galaxies (ETGs) in every field by modeling each of the sources within a 40" radius of the targets with a Sersic profile. Using a simple passive evolution model, we derive the expected location of the ETGs on the red sequence (RS) in the color-magnitude diagram for each of the fields of our sources. For seven targets, the model coincides with the position of the ETGs. A second approach involves a search for over densities. We compare the object densities of the sample as a whole and individually against control fields taken from the GOODS-S region of 3D-HST survey. With this method we determine the fields of 10 targets to be cluster candidates. Four cluster candidates are found by both methods. The two methods disagree in some cases, depending on the specific properties of each field. For the most distant radio galaxy in the 3CR catalog (3C257 at z = 2.47), we identify a population of bluer ETGs that lie on the expected location of the RS model for that redshift. This appears to be the general behavior of ETGs in our fields and it is possibly a signature of the evolution of such galaxies. Our results are consistent with half of the z > 1 radio galaxies being located in dense, rapidly evolving environments.

astro-ph.GA↗

arXiv2016

Powerful Activity in the Bright Ages. I. A Visible/IR Survey of High Redshift 3C Radio Galaxies and Quasars

We present new rest frame UV and visible observations of 22 high-redshift (1 < z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space Telescope's (HST) Wide Field Camera 3 (WFC3) instrument. Using a custom data reduction strategy in order to assure the removal of cosmic rays, persistence signal, and other data artifacts, we have produced high-quality science-ready images of the targets and their local environments. We observe targets with regions of UV emission suggestive of active star formation. In addition, several targets exhibit highly distorted host galaxy morphologies in the rest frame visible images. Photometric analyses reveals that brighter QSOs tend to be generally redder than their dimmer counterparts. Using emission line fluxes from the literature, we estimate that emission line contamination is relatively small in the rest frame UV images for the QSOs. Using archival VLA data, we have also created radio map overlays for each of our targets, allowing for analysis of the optical and radio axes alignment.

astro-ph.GA↗

arXiv2015

Optical Detection of the Pictor A Jet and Tidal Tail: Evidence against an IC/CMB jet

New images from the Hubble Space Telescope of the FRII radio galaxy Pictor A reveal a previously undiscovered tidal tail, as well as a number of jet knots coinciding with a known X-ray and radio jet. The tidal tail is approximately 5" wide (3 kpc projected), starting 18" (12 kpc) from the center of Pictor A, and extends more than 90" (60 kpc). The knots are part of a jet observed to be about 4' (160 kpc) long, extending to a bright hotspot. These images are the first optical detections of this jet, and by extracting knot flux densities through three filters we set constraints on emission models. While the radio and optical flux densities are usually explained by synchrotron emission, there are several emission mechanisms which might be used to explain the X-ray flux densities. Our data rule out Doppler boosted inverse Compton scattering as a source of the high energy emission. Instead, we find that the observed emission can be well described by synchrotron emission from electrons with a low energy index ($p\sim2$) that dominates the radio band, while a high energy index ($p\sim3$) is needed for the X-ray band and the transition occurs in the optical/infrared band. This model is consistent with a continuous electron injection scenario.

astro-ph.HE↗

arXiv2015

The Event Horizon of M87

The 6 billion solar mass supermassive black hole at the center of the giant elliptical galaxy M87 powers a relativistic jet. Observations at millimeter wavelengths with the Event Horizon Telescope have localized the emission from the base of this jet to angular scales comparable to the putative black hole horizon. The jet might be powered directly by an accretion disk or by electromagnetic extraction of the rotational energy of the black hole. However, even the latter mechanism requires a confining thick accretion disk to maintain the required magnetic flux near the black hole. Therefore, regardless of the jet mechanism, the observed jet power in M87 implies a certain minimum mass accretion rate. If the central compact object in M87 were not a black hole but had a surface, this accretion would result in considerable thermal near-infrared and optical emission from the surface. Current flux limits on the nucleus of M87 strongly constrain any such surface emission. This rules out the presence of a surface and thereby provides indirect evidence for an event horizon.

astro-ph.HE↗

arXiv2015

New Constraints on Quantum Gravity from X-ray and Gamma-Ray Observations

One aspect of the quantum nature of spacetime is its "foaminess" at very small scales. Many models for spacetime foam are defined by the accumulation power $α$, which parameterizes the rate at which Planck-scale spatial uncertainties (and thephase shifts they produce) may accumulate over large path-lengths. Here $α$ is defined by theexpression for the path-length fluctuations, $δ\ell$, of a source at distance $\ell$, wherein $δ\ell \simeq \ell^{1 - α} \ell_P^α$, with $\ell_P$ being the Planck length. We reassess previous proposals to use astronomical observations ofdistant quasars and AGN to test models of spacetime foam. We show explicitly how wavefront distortions on small scales cause the image intensity to decay to the point where distant objects become undetectable when the path-length fluctuations become comparable to the wavelength of the radiation. We use X-ray observations from {\em Chandra} to set the constraint $α\gtrsim 0.58$, which rules out the random walk model (with $α= 1/2$). Much firmer constraints canbe set utilizing detections of quasars at GeV energies with {\em Fermi}, and at TeV energies with ground-based Cherenkovtelescopes: $α\gtrsim 0.67$ and $α\gtrsim 0.72$, respectively. These limits on $α$ seem to rule out $α= 2/3$, the model of some physical interest.

astro-ph.CO↗