arXiv subjects

Kimberly Weaver

Publications and source records attributed to Kimberly Weaver.

6 recordsLinked to original sources

arXiv2026

AGN versus Star-formation: A MUSE Analysis of NGC 1365

Active galactic nuclei (AGN) and star formation feedback may heat and remove gas from galaxies in a process that quenches ongoing star formation and shapes the evolution of galaxies. Potential impacts from these processes can be seen in the complex and interconnected signatures of AGN and star formation activity throughout a galaxy. Here, we analyze archival integral field unit (IFU) data for the nearby Seyfert galaxy, NGC 1365, as observed with the Multi Unit Spectroscopic Explorer (MUSE) instrument on the Very Large Telescope (VLT). Our analysis probes the ionization and kinematic properties of NGC 1365 at high spatial resolution over unprecedentedly large physical scales (approximately 40 kpc), allowing us to trace the effects of feedback throughout nearly an entire galaxy. We use these optical IFU data in conjunction with observations from the James Webb Space Telescope (JWST) and Chandra X-ray Observatory to analyze and compare maps of emission line flux, ionization state, star formation, and gas kinematics. In doing so, we identify a region of BPT-identified unexpectedly high ionization relative to surrounding areas in the star forming arms, and work to identify its source, finding that shock heating may play a significant role. Results from this analysis allow us to place constraints on the relative impact of AGN and star formation processes on the star forming gas in NGC 1365, as well as begin to inform our understanding on the global impacts of feedback in galaxy populations as a whole.

astro-ph.GA↗

arXiv2023

LEM All-Sky Survey: Soft X-ray Sky at Microcalorimeter Resolution

The Line Emission Mapper (LEM) is an X-ray Probe with with spectral resolution ~2 eV FWHM from 0.2 to 2.5 keV and effective area >2,500 cm$^2$ at 1 keV, covering a 33 arcmin diameter Field of View with 15 arcsec angular resolution, capable of performing efficient scanning observations of very large sky areas and enabling the first high spectral resolution survey of the full sky. The LEM-All-Sky Survey (LASS) is expected to follow the success of previous all sky surveys such as ROSAT and eROSITA, adding a third dimension provided by the high resolution microcalorimeter spectrometer, with each 15 arcsec pixel of the survey including a full 1-2 eV resolution energy spectrum that can be integrated over any area of the sky to provide statistical accuracy. Like its predecessors, LASS will provide both a long-lasting legacy and open the door to the unknown, enabling new discoveries and delivering the baseline for unique GO studies. No other current or planned mission has the combination of microcalorimeter energy resolution and large grasp to cover the whole sky while maintaining good angular resolution and imaging capabilities. LASS will be able to probe the physical conditions of the hot phases of the Milky Way at multiple scales, from emission in the Solar system due to Solar Wind Charge eXchange, to the interstellar and circumgalactic media, including the North Polar Spur and the Fermi/eROSITA bubbles. It will measure velocities of gas in the inner part of the Galaxy and extract the emissivity of the Local Hot Bubble. By maintaining the original angular resolution, LASS will also be able to study classes of point sources through stacking. For classes with ~$10^4$ objects, it will provide the equivalent of 1 Ms of high spectral resolution data. We describe the technical specifications of LASS and highlight the main scientific objectives that will be addressed. (Abridged)

astro-ph.IM↗

arXiv2023

NuSTAR Observations of Four Mid-IR Selected Dual AGN Candidates in Galaxy Mergers

Mergers of galaxies are a ubiquitous phenomenon in the Universe and represent a natural consequence of the ``bottom-up'' mass accumulation and galaxy evolution cosmological paradigm. It is generally accepted that the peak of AGN accretion activity occurs at nuclear separations of $\lesssim10$ kpc for major mergers. Here we present new NuSTAR and XMM-Newton observations for a subsample of mid-IR preselected dual AGN candidates in an effort to better constrain the column densities along the line-of-sight for each system. Only one dual AGN candidate, J0841+0101, is detected as a single, unresolved source in the XMM-Newton and NuSTAR imaging, while the remaining three dual AGN candidates, J0122+0100, J1221+1137, and J1306+0735, are not detected with NuSTAR; if these non-detections are due to obscuration alone, these systems are consistent with being absorbed by column densities of log($N_{\rm{H}}/\rm{cm}^{-2}$) $\geq$ 24.9, 24.8, and 24.6, which are roughly consistent with previously inferred column densities in these merging systems. In the case of J0841+0101, the analysis of the 0.3-30 keV spectra reveal a line-of-sight column density of $N_{\rm{H}}\gtrsim10^{24}$ cm$^{-2}$, significantly larger than the column densities previously reported for this system and demonstrating the importance of the higher signal-to-noise XMM-Newton spectra and access to the $>10$ keV energies via NuSTAR. Though it is unclear if J0841+0101 truly hosts a dual AGN, these results are in agreement with the high obscuring columns expected in AGNs in late-stage mergers.

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arXiv2022

Simulations of AGN Driven Galactic Outflow Morphology and Content

Using a series of 3D relativistic hydrodynamical simulations of active galactic nuclei (AGN) we investigate how AGN power, a clumpy ISM structure, and AGN jet angle with respect to the galactic disk affect the morphology and content of the resulting galactic outflow. For low power AGN across three orders of magnitude of AGN luminosities ($10^{41}-10^{43}$ erg s$^{-1}$) our simulations did not show significant changes to either the morphology or total mass of the outflow. Changing the angle of the AGN jet with respect to the galaxy did show small changes in the total outflow mass of a factor of 2-3. Jets perpendicular to the galactic disk were created hot single phase outflows, while jets close to parallel with the disk created the outflows were multi-phase with equal parts warm and hot, and significant cold gas. Overall The final morphology of low power AGN outflows depends primarily on how the jet impacts and interacts with large, dense clouds in the clumpy ISM. These clouds can disrupt, deflect, split, or suppress the jet preventing it from leaving the galactic disk as a coherent structure. But for simulations with AGN luminosities $> 10^{44}$ erg s$^{-1}$ the ISM played a minor role in determining the morphology of the outflow with an undisrupted jet leaving the disk. The final morphology of AGN outflows is different for low power AGNs vs. high power AGNs with the final morphology of low power AGN outflows dependent on the ISM structure within the first kpc surrounding the AGN.

astro-ph.GA↗

arXiv2004

Intrinsic Absorption in the Spectrum of Mrk 279: Simultaneous Chandra, FUSE, and STIS Observations

We present a study of the intrinsic X-ray and far-ultraviolet absorption in the Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from the Chandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE). We also present FUSE observations made at three additional epochs. We detect the Fe K-alpha emission line in the Chandra spectrum, and its flux is consistent with the low X-ray continuum flux level of Mrk 279 at the time of the observation. Due to low signal-to-noise ratios in the Chandra spectrum, no O VII or O VIII absorption features are observable in the Chandra data, but the UV spectra reveal strong and complex absorption from HI and high-ionization species such as O VI, N V, and C IV, as well as from low-ionization species such as C III, N III, C II, and N II in some velocity components. The far-UV spectral coverage of the FUSE data provides information on high-order Lyman series absorption, which we use to calculate the optical depths and line and continuum covering fractions in the intrinsic HI absorbing gas in a self-consistent fashion. The UV continuum flux of Mrk 279 decreases by a factor of ~7.5 over the time spanning these observations and we discuss the implications of the response of the absorption features to this change. From arguments based on the velocities, profile shapes, covering fractions and variability of the UV absorption, we conclude that some of the absorption components, particularly those showing prominent low-ionization lines, are likely associated with the host galaxy of Mrk 279, and possibly with its interaction with a close companion galaxy, while the remainder arises in a nuclear outflow.

astro-ph↗

arXiv2002

Chandra Observations of the Evolving Core of the Starburst Galaxy NGC 253

Chandra observations of the core of the nearby starburst galaxy NGC 253 reveal a heavily absorbed source of hard X-rays embedded within the nuclear starburst region. The source has an unabsorbed, 2 to 10 keV luminosity of >=10^39 erg/s and photoionizes the surrounding gas. We observe this source through a dusty torus with a neutral absorbing column density of NH ~ 2x10^23 cm^-2. The torus is hundreds of pc across and collimates the starburst-driven nuclear outflow. We suggest that the ionizing source is an intermediate-mass black hole or a weakly accreting supermassive black hole, which may signal the beginnings or endings of AGN activity.

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