Mitchell Revalski

We present a complete and homogeneous analysis of the Ly α emission properties of the cosmic web at 3 ≲ z ≲ 5 as a function of the overdensity of Ly α emitters (LAEs) in the MUSE Ultra Deep Field (MUDF) and the MUSE Extremely Deep Field (MXDF). We identified 41 overdensities, probing environments that are δ ≈ 2 − 10 times denser than the field. We searched for extended emission down to surface brightness (SB) levels of 3 − 5 × 10 ⁻²⁰ erg s ⁻¹ cm ⁻² arcsec ⁻² , revealing filamentary structures beyond the scale of the circumgalactic medium, confirming that LAEs act as signposts of the cosmic web. A trend with overdensity emerges: non-detections are mainly at δ < 2, a ≈1 dex scatter in SB appears for 2 ≲ δ ≲ 3.5, and detections reach a maximum intrinsic SB of ≈2 × 10 ⁻¹⁹ erg s ⁻¹ cm ⁻² arcsec ⁻² for δ ≳ 3.5. Emitting regions occupy a fraction of projected area f _s ≈ 0.20 − 0.25 inside filaments, yielding a cosmological incidence for Ly α emission in the cosmic web ℓ (Ly α ) of ≈1.22, which is similar to the one of partially neutral Lyman limit systems. This analysis indicates that the emitting gas is partially ionized at moderate densities ( n _H ≈ 10 ⁻³ − 10 ⁻¹ cm ⁻³ ), likely tracing the denser spines of intergalactic filaments and embedded substructures. Finally, we forecast how oriented stacking in larger samples of overdensities from shallower observations could yield an expanded view of the cosmic web before the next-generation wide-field spectroscopic instruments become operational.

We present an investigation of the Tully–Fisher (TF) relation solely for galaxies hosting an active galactic nucleus (AGN). Using 22 galaxies with primary, z -independent distances, we find that active galaxies exhibit significantly larger scatter about all TF relations compared to each respective calibration for (largely) inactive galaxies. The larger scatter persists despite removal of the AGN contamination from the photometry of the type 1 AGNs via (1) careful surface brightness decompositions or (2) employing spectral energy distributions to constrain the light contribution of the AGN. These results suggest that the influence of an AGN on its host galaxy’s surface brightness may extend beyond the nucleus. We also calculate the percentage difference between TF and primary distances and find that TF-based distances are biased toward overestimation of the primary distances to active galaxies by anywhere from ∼5% to 10% for the optical/near-infrared and ∼15% for distances predicted from inverting the baryonic TF relation. As TF-based distances (especially the I band) are relied on heavily for analysis and modeling of the local peculiar velocity ( V _PEC ) field, we suggest that active galaxies be removed from future V _PEC modeling samples.

Assessing the contribution of ionizing sources to cosmic reionization is a central goal of extragalactic astrophysics. Understanding and quantifying ionizing escape remains challenging near the Epoch of Reionization. We present the highest-redshift Lyman continuum (LyC) emitter detected to date, MXDFz4.4, at z = 4.442 in the MUSE eXtremely Deep Field, observed only ∼0.25 Gyr after the end of reionization. A high-confidence Ly α line confirms the redshift. LyC flux is detected at 5.3 σ in the F435W filter with a flux of 4.2 ± 0.8 nJy, corresponding to a flux measurement at 5.2 σ . After correcting for the intrinsic production of LyC photons and the intergalactic medium opacity at z = 4.44, we derive high escape fractions, f _esc , ranging from 50% to 100%. We apply established low-redshift tracers of LyC escape and, for the first time at this redshift, promising Ly α morphological tracers such as the halo fraction (HF). Spectral energy distribution fitting indicates the presence of a recent burst of star formation; we explore its impact on the production and escape of ionizing photons. Ly α -based tracers of f _esc reveal a complex scenario in which the recent burst strongly influences LyC production and escape, combined with a more evolved stellar population. This interpretation is supported by UV diagnostics, including Σ _SFR and sSFR. Our results provide cautious support for the Ly α HF as a LyC escape tracer at high redshift. Considering the burst-driven enhancement in ionizing photon production and escape, we conclude that stochastic star formation in the early Universe likely plays a significant role in the contribution of galaxies to cosmic reionization.

We present new Chandra/ACIS-S imaging spectroscopy of two luminous type 2 quasars (QSO2s), FIRST J120041.4+314745 ( z = 0.116) and 2MASX J13003807+5454367 ( z = 0.088), and compare their X-ray emission with Hubble Space Telescope [O III ] λ 5007 morphologies and kinematics. Both systems show kiloparsec-scale soft X-ray emission. In FIRST J120041, the X-ray morphology is clumpy and closely follows the [O III ] structures, with surface-brightness peaks cospatial with the highest [O III ] velocities (600–750 km s ⁻¹ ) and broadest line widths (∼1700 km s ⁻¹ ). In 2MASX J130038, the X-ray emission is centrally concentrated and weakly correlated with rotational [O III ] kinematics. Spectral modeling indicates that photoionization dominates the soft X-rays in both quasars. The inferred hot-gas reservoirs are substantial, M _Xray ∼ 4.5 × 10 ⁸ M _⊙ (FIRST J120041) and M _Xray ∼ 1.8 × 10 ⁸ M _⊙ (2MASX J130038), exceeding the outflowing [O III ] masses by factors of ∼4 and ∼16. In 2MASX J130038, we identify a tentative blueshifted Fe XXVI Ly α line at E _rest = 7.14 ± 0.06 keV ( v ∼ 7600 km s ⁻¹ ), consistent with a hot wind confined to the inner few hundred parsecs. Combining these results with a broader sample of 12 QSO2s, we argue that luminous quasars evolve along a continuous feedback sequence regulated by progressive clearing of circumnuclear gas. As active galactic nucleus radiation and winds pierce the surrounding medium, systems transition from heavily enshrouded, compact configurations to phases where the X-ray and [O III ] components strongly couple and, eventually, to energetically dominant outflows. FIRST J120041 and 2MASX J130038 represent two points along this sequence, tracing the emergence and growth of hot winds as primary drivers of quasar-scale feedback.

We use deep MUSE data from the MUDF survey to investigate the cool gas around galaxies at redshifts 0.5 ≲ z ≲ 2. We constructed two samples: one sample for a down-the-barrel analysis, probing outflows via Mg II absorption against galaxy continua, and the other sample for projected galaxy pairs to examine the gas around the foreground galaxies in the transverse direction. From down-the-barrel stacked spectra, we detected blueshifted Mg II absorption, indicative of outflows, in which the absorption strength increases with stellar mass and star formation rate. Lower-mass galaxies exhibit weaker absorption, but higher outflow velocities, whereas higher-mass systems retain more cool gas with slower outflows. In the transverse direction, the absorption of Mg II decreases with the impact parameter, following a shallow profile. Comparing observations with radiative transfer models, we found that extrapolating an expanding halo model constrained with down-the-barrel measurements to halo scales overestimates the observed equivalent widths, likely due to the outflow geometry and the absence of the interstellar medium in the model. Our results highlight that mass, outflow geometry, and gas retention shape the cool circumgalactic medium, and that the combination of absorption and emission diagnostics provides powerful constraints on the properties of the cold halo gas.

Active galactic nuclei (AGN) winds play an important role in the coevolution of supermassive black holes and their host galaxies, yet their driving mechanisms and impact on star formation remain subjects of active investigation. Critically, the lack of X-ray integral field units currently limits our ability to acquire spatially resolved velocity information in the X-ray regime. However, instead, this can be achieved using the James Webb Space Telescope. As part of an ongoing investigation of the nuclear feedback processes in the nearby luminous AGN NGC 7469, we present an analysis of the kinematics of the X-ray emitting outflows using near-infrared footprint lines such as [Mg viii ] λ 3.03 μ m. These high-ionization emission lines are associated with the same gas analyzed in the X-ray, and thus can be used to probe the footprint of the X-ray wind’s velocity structure and ionization state. Thanks to the wide wavelength range available with JWST we also use nebular (e.g., [S iv ] λ 10.51 μ m) and coronal (e.g., [Ne v ] λ 14.32 μ m) emission lines to offer a comprehensive multiphase view of the outflows. We present mass and kinetic energy outflow rates and find that while the feedback processes in NGC 7469 are not efficient by theoretical benchmarks, the most massive and energetic component is the high ionization X-ray gas.

Compact galaxy groups are ideal laboratories for studying the effects of interactions between active galactic nuclei (AGN) and multiple nearby galaxies. Recent JWST observations of the nearby compact group Stephan’s Quintet highlight tidal flows between the interacting galaxies as well as outflows from the active galaxy NGC 7319. To study the kinematics on a large scale throughout the group, we obtained spatially resolved long-slit spectra of Stephan’s Quintet at multiple slit positions with Apache Point Observatory’s Kitt Peak Ohio State Multi-Object Spectrograph. We fit multiple Gaussians to the H α λ 6563 and [N II ] λλ 6548, 6583 emission lines to isolate the different kinematic components. We used the kinematics to develop the first biconical outflow model of the narrow-line region of NGC 7319. Using a combination of galactic rotation models, biconical outflow models, and kinematic maps of the ionized gas, we disentangled the outflows, rotation, and tidal flows in the group. We found outflow radial velocities up to 550 km s ⁻¹ peaking at 2.6 kpc from the central supermassive black hole, and a transition from AGN-powered outflows to gravitationally powered tidal flows at a projected distance between 2.4 and 6.3 kpc. We performed a line ratio analysis and determined the gas shows Seyfert-like ionization out to 6.3 kpc (projected), which supports our finding that gas outside this radius is predominantly powered by tidal flows. Our separation of kinematic components in Stephan’s Quintet will enable future studies of the physical conditions and dynamical forces in the ionized gas to better quantify the feeding and feedback processes of AGN in compact groups.

We present spatially resolved mass outflow rates of the ionized and molecular gas in the narrow-line region of the Seyfert 1 galaxy NGC 3227. Using long-slit spectroscopy and [O III ] imaging from from the Hubble Space Telescope’s Space Telescope Imaging Spectrograph and Apache Point Observatory’s Kitt Peak Ohio State Multi-Object Spectrograph, in conjunction with Cloudy photoionization models and emission-line diagnostics, we find a peak ionized mass outflow rate of M ̇ ion = 19.9 ± 9.2 M _⊙ yr ⁻¹ at a distance of 47 ± 6 pc from the supermassive black hole (SMBH). Using archival data from the Gemini-North Near-infrared Field Spectrograph measuring H ₂ 2.1218 μ m emission, we find a maximum peak warm molecular outflow rate of M ̇ H 2 ≤ 9 × 10 − 4 M _⊙ yr ⁻¹ at a distance of 36 ± 6 pc from the SMBH. Using archival data from the Atacama Large Millimeter/submillimeter Array measuring CO(2–1) emission, we find a maximum peak cold molecular gas mass outflow rate of M ̇ CO ≤ 23.1 M _⊙ yr ⁻¹ at a distance of 57 ± 6 pc from the SMBH. For the first time, we calculate spatially resolved gas evacuation timescales for the cold molecular gas reservoirs ostensibly sourcing the outflows, and find that gas evacuating to ∼400 pc from the SMBH occurs on timescales of 10 ^6.0 –10 ^7.6 yr. These results indicate that the multiphase active galactic nucleus (AGN) outflows are effective in clearing the inner few hundred parsecs of NGC 3227’s gas content on timescales that may set the AGN duty cycle of 10 ⁵ –10 ⁸ yr.

Active galactic nuclei (AGN) are known to drive ionized gas into their host galaxies, which may affect the evolution of both the central supermassive black holes and their hosts. In the case of NGC 3516, a nearby Seyfert 1 galaxy, these AGN winds have historically proven difficult to disentangle from galactic rotation. Using long slit spectroscopy at multiple position angles from the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Apache Point Observatory Kitt Peak Ohio State Multi Object Spectrograph, we separate these kinematic components by fitting multiple Gaussians to the Hα, N II, Hβ, and O III emission lines along the slits. We present a biconical outflow model that agrees well with the observed kinematics of the outflowing gas in the narrow-line region (NLR). Our results indicate that the structure of the O III emission is explained by dusty gas spirals in the galactic disk that are illuminated by the ionizing bicone, which is viewed along one edge, resulting in the complex nuclear kinematics. Our view into the bicone edge is consistent with the multiple, deep components of ionized absorption lines seen in UV and X-ray spectra of NGC 3516. The observed turnover in the velocity of the NLR clouds matches that from a simple dynamical model of radiative acceleration by the AGN and gravitational deceleration by the AGN and galaxy, indicating they are the principal forces at work on the gas clouds. Finally, the model launch radii indicate that the outflowing clouds originate primarily from the inner dusty spirals near the AGN.

Active galactic nuclei (AGN) are known to drive ionized gas into their host galaxies, which may affect the evolution of both the central supermassive black holes and their hosts. In the case of NGC 3516, a nearby Seyfert 1 galaxy, these AGN winds have historically proven difficult to disentangle from galactic rotation. Using long-slit spectroscopy at multiple position angles from Hubble Space Telescope’s Space Telescope Imaging Spectrograph and Apache Point Observatory’s Kitt Peak Ohio State Multi-Object Spectrograph, we separate these kinematic components by fitting multiple Gaussians to the Hα, [N II], Hβ, and [O III] emission lines along the slits. We present a biconical outflow model that agrees well with the observed kinematics of the outflowing gas in the narrow-line region (NLR). Our results indicate that the structure of the [O III] emission is explained by dusty gas spirals in the galactic disk that are illuminated by the ionizing bicone, which is viewed along one edge, resulting in the complex nuclear kinematics. Our view into the bicone edge is consistent with the multiple, deep components of ionized absorption lines seen in UV and X-ray spectra of NGC 3516. The observed turnover in the velocity of the NLR clouds matches that from a simple dynamical model of radiative acceleration by the AGN and gravitational deceleration by the AGN and galaxy, indicating they are the principal forces at work on the gas clouds. Finally, the model launch radii indicate that the outflowing clouds originate primarily from the inner dusty spirals near the AGN.