arXiv subjects

D. S. N. Rupke

Publications and source records attributed to D. S. N. Rupke.

14 recordsLinked to original sources

arXiv2026

A cosmic collision in the making: JWST/NIRISS reveals a merging and maturing protocluster core at z~3 around a red quasar

We report the discovery of ``The Step'', a dense protocluster at z=3 revealed by JWST/NIRISS Wide-Field Slitless Spectroscopy (WFSS) of the field around the luminous quasar and starburst SDSSJ165202.64+172852.3. The protocluster contains at least 18 member galaxies and exhibits two substructures in the 3D position-velocity space - notably a distinctive step-like distribution, from which the nickname derives. We propose that the Step may be undergoing a merger of two haloes, which could also explain the large velocity span (700-850km/s) between galaxies along the densest line of sight. This sightline contains seven galaxies within 70 projected kpc from the quasar, consistent with a remarkably dense protocluster core. We derive a galaxy overdensity of a factor >100 in the core and >15 within 1 Mpc$^2$, making it one of the densest structures known at this redshift, and a very massive halo of $13.1 < log M_{\rm halo}/ M_\odot < 13.8$, which suggests the structure could potentially evolve into a massive, Coma-like cluster at z=0. Compared to the field, the star-forming galaxies in the Step show slightly elevated levels of star formation. Yet, we find two quiescent galaxies with strong D4000 breaks and no evidence for ongoing star formation. Compared to other z=3 protoclusters, the Step exhibits similar or slightly suppressed star-forming activity. We also identify two new AGN candidates and find tentative evidence for an enhanced AGN fraction (10-20%) compared to the field. The protocluster constitutes one of the emerging handful of maturing structures at 2 < z < 4 that host both star-forming and quenched galaxies. This redshift regime may thus be a key transitional epoch for cluster studies, where overdensities transition from being the most active sites of star formation in the early Universe towards shaping the massive passive ellipticals seen in the cores of today's clusters.

astro-ph.GA↗

arXiv2023

First results from the JWST Early Release Science Program Q3D: Benchmark Comparison of Optical and Mid-IR Tracers of a Dusty, Ionized Red Quasar Wind at z=0.435

The [OIII] 5007 A emission line is the most common tracer of warm, ionized outflows in active galactic nuclei across cosmic time. JWST newly allows us to use mid-infrared spectral features at both high spatial and spectral resolution to probe these same winds. Here we present a comparison of ground-based, seeing-limited [OIII] and space-based, diffraction-limited [SIV] 10.51 micron maps of the powerful, kiloparsec-scale outflow in the Type 1 red quasar SDSS J110648.32+480712.3. The JWST data are from the Mid-InfraRed Instrument (MIRI). There is a close match in resolution between the datasets (0."6), in ionization potential of the O$^{+2}$ and S$^{+3}$ ions (35 eV), and in line sensitivity (1e-17 to 2e-17 erg/s/cm$^2$/arcsec$^2$). The [OIII] and [SIV] line shapes match in velocity and linewidth over much of the 20 kpc outflowing nebula, and [SIV] is the brightest line in the rest-frame 3.5-19.5 micron range, demonstrating its usefulness as a mid-IR probe of quasar outflows. [OIII] is nevertheless intriniscally brighter and provides better contrast with the point-source continuum, which is strong in the mid-IR. There is a strong anticorrelation of [OIII]/[SIV] with average velocity, which is consistent with a scenario of differential obscuration between the approaching (blueshifted) and receding (redshifted) sides of the flow. The dust in the wind may also obscure the central quasar, consistent with models that attribute red quasar extinction to dusty winds.

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arXiv2021

Exploring the Dust Content of Galactic Halos with Herschel. IV. NGC 3079

We present the results from an analysis of deep Herschel far-infrared observations of the edge-on disk galaxy NGC 3079. The PSF-cleaned PACS images at 100 and 160 um display a 25 kpc x 25 kpc X-shape structure centered on the nucleus that is similar in extent and orientation to that seen in Halpha, X-rays, and the far-ultraviolet. One of the dusty filaments making up this structure is detected in the SPIRE 250 um map out to ~25 kpc from the nucleus. The match between the far-infrared filaments and those detected at other wavelengths suggests that the dusty material has been lifted out of the disk by the same large-scale galactic wind that has produced the other structures in this object. A closer look at the central 10 kpc x 10 kpc region provides additional support for this scenario. The dust temperatures traced by the 100-to-160 um flux ratios in this region are enhanced within a biconical region centered on the active galactic nucleus, aligned along the minor axis of the galaxy, and coincident with the well-known double-lobed cm-wave radio structure and Halpha-X-ray nuclear superbubbles. PACS imaging spectroscopy of the inner 6-kpc region reveals broad [C II] 158 um emission line profiles and OH 79 um absorption features along the minor axis of the galaxy with widths well in excess of those expected from beam smearing of the disk rotational motion. This provides compelling evidence that the cool material traced by the [C II] and OH features directly interacts with the nuclear ionized and relativistic outflows traced by the Halpha, X-ray, and radio emission.

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arXiv2019

AGN feedback in a galaxy merger: Multi-phase, galaxy-scale outflows including a fast molecular gas blob ~6 kpc away from IRAS F08572+3915

To understand the role that AGN feedback plays in galaxy evolution we need in-depth studies of the multi-phase structure and energetics of galaxy-wide outflows. In this work we present new, deep ($\sim$50 hr) NOEMA CO(1-0) line observations of the molecular gas in the powerful outflow driven by the AGN in the ultra-luminous infrared galaxy IRAS F08572+3915. We spatially resolve the outflow, finding that its most likely configuration is a wide-angle bicone aligned with the kinematic major axis of the rotation disk. The molecular gas in the wind reaches velocities up to approximately $\pm$1200 km s$^{-1}$ and transports nearly 20% of the molecular gas mass in the system. We detect a second outflow component located $\sim$6 kpc north-west from the galaxy moving away at $\sim$900 km s$^{-1}$, which could be the result of a previous episode of AGN activity. The total mass and energetics of the outflow, which includes contributions from the ionized, neutral, warm and cold molecular gas phases is strongly dominated by the cold molecular gas. In fact, the molecular mass outflow rate is higher than the star formation rate, even if we only consider the gas in the outflow that is fast enough to escape the galaxy, which accounts for about $\sim$40% of the total mass of the outflow. This results in an outflow depletion time for the molecular gas in the central $\sim$1.5 kpc region of only $\sim3$ Myr, a factor of $\sim2$ shorter than the depletion time by star formation activity.

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arXiv2017

Quasar Feedback in the Ultraluminous Infrared Galaxy F11119+3257: Connecting the Accretion Disk Wind with the Large-Scale Molecular Outflow

In Tombesi et al. (2015), we reported the first direct evidence for a quasar accretion disk wind driving a massive molecular outflow. The target was F11119+3257, an ultraluminous infrared galaxy (ULIRG) with unambiguous type-1 quasar optical broad emission lines. The energetics of the accretion disk wind and molecular outflow were found to be consistent with the predictions of quasar feedback models where the molecular outflow is driven by a hot energy-conserving bubble inflated by the inner quasar accretion disk wind. However, this conclusion was uncertain because the energetics were estimated from the optically thick OH 119 um transition profile observed with Herschel. Here, we independently confirm the presence of the molecular outflow in F11119+3257, based on the detection of broad wings in the CO(1-0) profile derived from ALMA observations. The broad CO(1-0) line emission appears to be spatially extended on a scale of at least ~7 kpc from the center. Mass outflow rate, momentum flux, and mechanical power of (80-200) R_7^{-1} M_sun/yr, (1.5-3.0) R_7^{-1} L_AGN/c, and (0.15-0.40)% R_7^{-1} L_AGN are inferred from these data, assuming a CO-to-H_2 conversion factor appropriate for a ULIRG (R_7 is the radius of the outflow normalized to 7 kpc and L_AGN is the AGN luminosity). These rates are time-averaged over a flow time scale of 7x10^6 yrs. They are similar to the OH-based rates time-averaged over a flow time scale of 4x10^5 yrs, but about a factor 4 smaller than the local ("instantaneous"; <10^5 yrs) OH-based estimates cited in Tombesi et al. The implications of these new results are discussed in the context of time-variable quasar-mode feedback and galaxy evolution. The need for an energy-conserving bubble to explain the molecular outflow is also re-examined.

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arXiv2016

The Complete Ultraviolet Spectrum of the Archetypal "Wind-Dominated" Quasar Mrk~231: Absorption and Emission from a High-Speed Dusty Nuclear Outflow

New near- and far-ultraviolet (NUV and FUV) HST spectra of Mrk 231, the nearest quasar known, are combined with ground-based optical spectra to study the remarkable dichotomy between the FUV and NUV-optical spectral regions in this object. The FUV emission-line features are faint, broad, and highly blueshifted (up to ~7000 km/s), with no significant accompanying absorption. In contrast, the profiles of the NUV absorption features resemble those of the optical Na I D, He I, and Ca II H and K lines, exhibiting broad blue-shifted troughs that overlap in velocity space with the FUV emission-line features and indicate a dusty, high-density and patchy broad absorption line (BAL) screen covering ~90% of the observed continuum source at a distance less than ~2 - 20 pc. The FUV continuum emission does not show the presence of any obvious stellar features and is remarkably flat compared with the steeply declining NUV continuum. The NUV (FUV) features and continuum emission have not varied significantly over the past ~22 (3) years and are unresolved on scales ~40 (170) pc. These results favor an AGN origin for the NUV - FUV line and continuum emission. The observed FUV line emission is produced in the outflowing BAL cloud system, while the Balmer lines arise primarily from the standard broad line region seen through the dusty BAL screen. Our data are inconsistent with the recently proposed binary black hole model. We argue instead that Mrk~231 is the nearest example of weak-lined "wind-dominated" quasars with high Eddington ratios and geometrically thick ("slim") accretion disks; these quasars are likely more common in the early universe.

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arXiv2013

Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel

We report the results from a systematic search for molecular (OH-119 um) outflows with Herschel-PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7-um silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than -50 km/sec, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (~145 degrees) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km/sec, is seen in only 4 objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of ~-1000 km/sec are measured in several objects, but median outflow velocities are typically ~-200 km s^{-1}. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large AGN fractions and luminosities [log (L_AGN / L_sun) > 11.8 +/- 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. In contrast, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.

astro-ph.CO↗

arXiv2012

The Surprising Absence of Absorption in the Far-Ultraviolet Spectrum of Mrk 231

Mrk 231, the nearest (z = 0.0422) quasar, hosts both a galactic-scale wind and a nuclear-scale iron low-ionization broad absorption line (FeLoBAL) outflow. We recently obtained a far-ultraviolet (FUV) spectrum of this object covering ~1150 - 1470 A with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. This spectrum is highly peculiar, highlighted by the presence of faint (~< 2% of predictions based on H-alpha), broad (>~ 10,000 km/s at the base), and highly blueshifted (centroid at ~ -3500 km/s) Ly-alpha emission. The FUV continuum emission is slightly declining at shorter wavelengths (consistent with F_lambda ~ lambda^1.7) and does not show the presence of any obvious photospheric or wind stellar features. Surprisingly, the FUV spectrum also does not show any unambiguous broad absorption features. It thus appears to be dominated by the AGN, rather than hot stars, and virtually unfiltered by the dusty FeLoBAL screen. The observed Ly-alpha emission is best explained if it is produced in the outflowing BAL cloud system, while the Balmer lines arise primarily from the standard broad emission line region seen through the dusty (A_V ~ 7 mag.) broad absorption line region. Two possible geometric models are discussed in the context of these new results.

astro-ph.CO↗

arXiv2012

An Integral Field Study of Abundance Gradients in Nearby LIRGs

We present for the first time metallicity maps generated using data from the Wide Field Spectrograph (WiFeS) on the ANU 2.3m of 9 Luminous Infrared Galaxies (LIRGs) and discuss the abundance gradients and distribution of metals in these systems. We have carried out optical integral field spectroscopy (IFS) of several several LIRGs in various merger phases to investigate the merger process. In a major merger of two spiral galaxies with preexisting disk abundance gradients, the changing distribution of metals can be used as a tracer of gas flows in the merging system as low metallicity gas is transported from the outskirts of each galaxy to their nuclei. We employ this fact to probe merger properties by using the emission lines in our IFS data to calculate the gas-phase metallicity in each system. We create abundance maps and subsequently derive a metallicity gradient from each map. We compare our measured gradients to merger stage as well as several possible tracers of merger progress and observed nuclear abundances. We discuss our work in the context of previous abundance gradient observations and compare our results to new galaxy merger models which trace metallicity gradient. Our results agree with the observed flattening of metallicity gradients as a merger progresses. We compare our results with new theoretical predictions that include chemical enrichment. Our data show remarkable agreement with these simulations.

astro-ph.CO↗

arXiv2011

NGC 839: Shocks in an M82-like Superwind

We present observations of NGC 839 made with the Wide Field Spectrograph (WiFeS) on the ANU 2.3m telescope. Our data cover a region 25" x 60" at a spatial resolution of ~1.5". The long axis of the field is aligned with the superwind we have discovered in this starburst galaxy. The data cover the range of 3700-7000 Å, with a spectral resolution R~7000 in the red, and R~3000 in the blue. We find that the stellar component of the galaxy is strongly dominated by a fast rotating intermediate-age (~400 Myr) A-Type stellar population, while the gas is concentrated in a bi-conical polar funnel. We have generated flux distributions, emission line ratio diagnostics and velocity maps in both emission and absorption components. We interpret these in the context of a new grid of low-velocity shock models appropriate for galactic-scale outflows. These models are remarkably well fit to the data, providing for the first time model diagnostics for shocks in superwinds and strongly suggesting that shock excitation is largely responsible for the extended LINER emission in the outflowing gas in NGC 839. Our work may have important implications both for extended LINER emission seen in other galaxies, as well as in the interpretation of objects with "composite" spectra. Finally, we present a scenario for the formation of E+A galaxies based upon our observations of NGC 839, and its relation to M82.

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arXiv2009

MMTF: The Maryland-Magellan Tunable Filter

This paper describes the Maryland-Magellan Tunable Filter (MMTF) on the Magellan-Baade 6.5-meter telescope. MMTF is based on a 150-mm clear aperture Fabry-Perot (FP) etalon that operates in low orders and provides transmission bandpass and central wavelength adjustable from ~5 to ~15 A and from ~5000 to over ~9200 A, respectively. It is installed in the Inamori Magellan Areal Camera and Spectrograph (IMACS) and delivers an image quality of ~0.5" over a field of view of 27' in diameter (monochromatic over ~10'). This versatile and easy-to-operate instrument has been used over the past three years for a wide variety of projects. This paper first reviews the basic principles of FP tunable filters, then provides a detailed description of the hardware and software associated with MMTF and the techniques developed to observe with this instrument and reduce the data. The main lessons learned in the course of the commissioning and implementation of MMTF are highlighted next, before concluding with a brief outlook on the future of MMTF and of similar facilities which are soon coming on line.

astro-ph.IM↗

arXiv2009

Warm Molecular Hydrogen in the Galactic Wind of M82

We report the detection of a complex of extraplanar warm H_2 knots and filaments extending more than ~3 kpc above and below the galactic plane of M82, roughly coincident with the well-known galactic wind in this system. Comparisons of these data with published results at other wavelengths provide quantitative constraints on the topology, excitation, heating, and stability against disruption of the wind-entrained molecular ISM in this prototypical galactic wind. Deep H_2 2.12 um observations such as these represent a promising new method to study the elusive but potentially important molecular component of galactic winds.

astro-ph.CO↗

arXiv2009

A Deep HST H-Band Imaging Survey of Massive Gas-Rich Mergers. II. The QUEST PG QSOs

We report the results from a deep HST NICMOS H-band imaging survey of 28 z < 0.3 QSOs from the Palomar-Green (PG) sample. This program is part of QUEST (Quasar / ULIRG Evolution STudy) and complements a similar set of data on 26 highly-nucleated ULIRGs presented in Paper I. Our analysis indicates that the fraction of QSOs with elliptical hosts is higher among QSOs with undetected far-infrared (FIR) emission, small infrared excess, and luminous hosts. The hosts of FIR-faint QSOs show a tendency to have less pronounced merger-induced morphological anomalies and larger QSO-to-host luminosity ratios on average than the hosts of FIR-bright QSOs, consistent with late-merger evolution from FIR-bright to FIR-faint QSOs. The spheroid sizes and total host luminosities of the radio-quiet PG QSOs in our sample are statistically indistinguishable from the ULIRG hosts presented in Paper I, while those of radio-loud PG QSOs are systematically larger and more luminous. ULIRGs and PG QSOs with elliptical hosts fall near, but not exactly on, the fundamental plane of inactive spheroids. We confirm the systematic trend noted in Paper I for objects with small (< 2 kpc) spheroids to be up to ~1 mag. brighter than inactive spheroids. The host colors and wavelength dependence of their sizes support the idea that these deviations are due at least in part to non-nuclear star formation. However, the amplitudes of these deviations does not depend on host R-H colors. Taken at face value (i.e., no correction for extinction or the presence of a young stellar population), the H-band spheroid-host luminosities imply BH masses ~5 -- 200 x 10^7 M_sun and sub-Eddington mass accretion rates for both QSOs and ULIRGs. These results are compared with published BH mass estimates derived from other methods. (abridged)

astro-ph.CO↗

arXiv2009

Spitzer Quasar and ULIRG Evolution Study (QUEST). IV. Comparison of 1-Jy Ultraluminous Infrared Galaxies with Palomar-Green Quasars

We report the results from a comprehensive study of 74 ultraluminous infrared galaxies (ULIRGs) and 34 Palomar-Green (PG) quasars within z ~ 0.3$ observed with the Spitzer Infrared Spectrograph (IRS). The contribution of nuclear activity to the bolometric luminosity in these systems is quantified using six independent methods that span a range in wavelength and give consistent results within ~ +/-10-15% on average. The average derived AGN contribution in ULIRGs is ~35-40%, ranging from ~15-35% among "cool" (f_25/f_60 =< 0.2) optically classified HII-like and LINER ULIRGs to ~50 and ~75% among warm Seyfert 2 and Seyfert 1 ULIRGs, respectively. This number exceeds ~80% in PG QSOs. ULIRGs fall in one of three distinct AGN classes: (1) objects with small extinctions and large PAH equivalent widths are highly starburst-dominated; (2) systems with large extinctions and modest PAH equivalent widths have larger AGN contributions, but still tend to be starburst-dominated; and (3) ULIRGs with both small extinctions and small PAH equivalent widths host AGN that are at least as powerful as the starbursts. The AGN contributions in class 2 ULIRGs are more uncertain than in the other objects, and we cannot formally rule out the possibility that these objects represent a physically distinct type of ULIRGs. A morphological trend is seen along the sequence (1)-(2)-(3), in general agreement with the standard ULIRG - QSO evolution scenario and suggestive of a broad peak in extinction during the intermediate stages of merger evolution. However, the scatter in this sequence, implies that black hole accretion, in addition to depending on the merger phase, also has a strong chaotic/random component, as in local AGN. (abridged)

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