21 research outputs found
Galactic Scale Feedback Observed in the 3C 298 Quasar Host Galaxy
We present high angular resolution multi-wavelength data of the 3C 298
radio-loud quasar host galaxy (z=1.439) taken using the W.M. Keck Observatory
OSIRIS integral field spectrograph with adaptive optics, Atacama Large
Millimeter/submillimeter Array (ALMA), Hubble Space Telescope (HST) WFC3, and
the Very Large Array (VLA). Extended emission is detected in the rest-frame
optical nebular emission lines H, [OIII], H, [NII], and [SII],
as well as molecular lines CO (J=3-2) and (J=5-4). Along the path of 3C 298's
relativistic jets we detect conical outflows of ionized gas with velocities up
to 1700 km s and outflow rate of 450-1500 Myr. Near the
spatial center of the conical outflow, CO (J=3-2) emission shows a molecular
gas disc with a total molecular mass () of
6.6M. On the molecular disc's blueshifted side
we observe a molecular outflow with a rate of 2300 Myr and
depletion time scale of 3 Myr. We detect no narrow H emission in the
outflow regions, suggesting a limit on star formation of 0.3
Myrkpc. Quasar driven winds are evacuating the molecular
gas reservoir thereby directly impacting star formation in the host galaxy. The
observed mass of the supermassive black hole is M and
we determine a dynamical bulge mass of 1-1.7
M. The bulge mass of 3C 298 resides 2-2.5 orders of magnitude below
the expected value from the local M relationship. A second
galactic disc observed in nebular emission is offset from the quasar by 9 kpc
suggesting the system is an intermediate stage merger. These results show that
galactic scale negative feedback is occurring early in the merger phase of 3C
298, well before the coalescence of the galactic nuclei and assembly on the
local relationship.Comment: 23 pages, 11 figures, 4 tables, Accepted for publication in the
Astrophysical Journa
Providing stringent star formation rate limits of z2 QSO host galaxies at high angular resolution
We present integral field spectrograph (IFS) with laser guide star adaptive
optics (LGS-AO) observations of z=2 quasi-stellar objects (QSOs) designed to
resolve extended nebular line emission from the host galaxy. Our data was
obtained with W. M. Keck and Gemini-North Observatories using OSIRIS and NIFS
coupled with the LGS-AO systems. We have conducted a pilot survey of five QSOs,
three observed with NIFS+AO and two observed with OSIRIS+AO at an average
redshift of z=2.15. We demonstrate that the combination of AO and IFS provides
the necessary spatial and spectral resolutions required to separate QSO
emission from its host. We present our technique for generating a PSF from the
broad-line region of the QSO and performing PSF subtraction of the QSO emission
to detect the host galaxy. We detect H and [NII] for two sources, SDSS
J1029+6510 and SDSS J0925+06 that have both star formation and extended
narrow-line emission. Assuming that the majority of narrow-line H is
from star formation, we infer a star formation rate for SDSS J1029+6510 of 78.4
Myr originating from a compact region that is kinematically
offset by 290 - 350 km/s. For SDSS J0925+06 we infer a star formation rate of
29 Myr distributed over three clumps that are spatially offset
by 7 kpc. The null detections on three of the QSOs are used to infer
surface brightness limits and we find that at 1.4 kpc distance from the QSO
that the un-reddened star formation limit is 0.3
Myrkpc. If we assume a typical extinction values for z=2
type-1 QSOs, the dereddened star formation rate for our null detections would
be 0.6 Myrkpc. These IFS observations indicate that
if star formation is present in the host it would have to occur diffusely with
significant extinction and not in compact, clumpy regions.Comment: 17 pages, 7 figures, 7 tables, Accepted to Ap
Cold Mode Gas Accretion on Two Galaxy Groups at z2
We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS)
observations of rest-frame UV emission lines , C IV 1548 \AA, 1550\AA and He II 1640 \AA observed in the circumgalactic
medium (CGM) of two radio-loud quasar host galaxies. We detect extended
emission on 80-90 kpc scale in in both systems with C IV, and He
II emission also detected out to 30-50 kpc. All emission lines show kinematics
with a blue and redshifted gradient pattern consistent with velocities seen in
massive dark matter halos and similar to kinematic patterns of inflowing gas
seen in hydrodynamical simulations. Using the kinematics of both resolved emission and absorption, we can confirm that both kinematic
structures are associated with accretion. Combining the KCWI data with
molecular gas observations with Atacama Large Millimeter/submillimeter Array
(ALMA) and high spatial resolution of ionized gas with Keck OSIRIS, we find
that both quasar host galaxies reside in proto-group environments at . We
estimate M of warm-ionized gas within 30-50 kpc from
the quasar that is likely accreting onto the galaxy group. We estimate inflow
rates of 60-200 Myr, within an order of magnitude of the outflow
rates in these systems. In the 4C 09.17 system, we detect narrow gas streams
associated with satellite galaxies, potentially reminiscent of ram-pressure
stripping seen in local galaxy groups and clusters. We find that the quasar
host galaxies reside in dynamically complex environments, with ongoing mergers,
gas accretion, ISM stripping, and outflows likely playing an important role in
shaping the assembly and evolution of massive galaxies at cosmic noon.Comment: 24 pages, 11 figures, 6 tabes. Accepted for publication in MNRA
Powerful winds in high-redshift obscured and red quasars
Quasar-driven outflows must have made their most significant impact on galaxy formation during the epoch when massive galaxies were forming most rapidly. To study the impact of quasar feedback, we conducted rest-frame optical integral field spectrograph (IFS) observations of three extremely red quasars (ERQs) and one type-2 quasar at z = 2–3, obtained with the NIFS and OSIRIS instruments at the Gemini North and W. M. Keck Observatory with the assistance of laser-guided adaptive optics. We use the kinematics and morphologies of the [O III] 5007 Å and H α 6563 Å emission lines redshifted into the near-infrared to gauge the extents, kinetic energies and momentum fluxes of the ionized outflows in the quasars host galaxies. For the ERQs, the galactic-scale outflows are likely driven by radiation pressure in a high column density environment or due to an adiabatic shock. The outflows in the ERQs carry a significant amount of energy ranging from 0.05 to 5 per cent of the quasar’s bolometric luminosity, powerful enough to have a significant impact on the quasar host galaxies. The outflows are resolved on kpc scales, the observed outflow sizes are generally smaller than other ionized outflows observed at high redshift. The high ratio between the momentum flux of the ionized outflow and the photon momentum flux from the quasar accretion disc and high nuclear obscuration makes these ERQs great candidates for transitional objects where the outflows are likely responsible for clearing material in the inner regions of each galaxy, unveiling the quasar accretion disc at optical wavelengths
Size–Luminosity Scaling Relations of Local and Distant Star-forming Regions
We investigate star forming scaling relations using Bayesian inference on a comprehensive data sample of low- (z < 0.1) and high-redshift (1 < z < 5) star forming regions. This full data set spans a wide range of host galaxy stellar mass (M∗∼10^6−10^(11)M⊙) and clump star formation rates (SFR ∼10^(−5)−10^2M⊙yr^(−1)). We fit the power-law relationship between the size (r_(Hα)) and luminosity (L_(Hα)) of the star forming clumps using the Bayesian statistical modeling tool Stan that makes use of Markov Chain Monte Carlo (MCMC) sampling techniques. Trends in the scaling relationship are explored for the full sample and subsets based on redshift and selection effects between samples. In our investigation we find no evidence of redshift evolution of the size-luminosity scaling relationship, nor a difference in slope between lensed and unlensed data. There is evidence of a break in the scaling relationship between high and low star formation rate surface density (Σ_(SFR)) clumps. The size-luminosity power law fit results are L_(Hα) ∼ r^(2.8)_(Hα) and L_(Hα) ∼ r^(1.7)_(Hα) for low and high Σ_(SFR) clumps, respectively. We present a model where star forming clumps form at locations of gravitational instability and produce an ionized region represented by the Strömgren radius. A radius smaller than the scale height of the disk results in a scaling relationship of L ∝ r^3 (high Σ_(SFR) clumps), and a scaling of L ∝ r2^ (low Σ_(SFR) clumps) if the radius is larger than the disk scale height
Characterizing and Improving the Data Reduction Pipeline for the Keck OSIRIS Integral Field Spectrograph
OSIRIS is a near-infrared (1.0--2.4 m) integral field spectrograph
operating behind the adaptive optics system at Keck Observatory, and is one of
the first lenslet-based integral field spectrographs. Since its commissioning
in 2005, it has been a productive instrument, producing nearly half the laser
guide star adaptive optics (LGS AO) papers on Keck. The complexity of its raw
data format necessitated a custom data reduction pipeline (DRP) delivered with
the instrument in order to iteratively assign flux in overlapping spectra to
the proper spatial and spectral locations in a data cube. Other than bug fixes
and updates required for hardware upgrades, the bulk of the DRP has not been
updated since initial instrument commissioning. We report on the first major
comprehensive characterization of the DRP using on-sky and calibration data. We
also detail improvements to the DRP including characterization of the flux
assignment algorithm; exploration of spatial rippling in the reduced data
cubes; and improvements to several calibration files, including the
rectification matrix, the bad pixel mask, and the wavelength solution. We
present lessons learned from over a decade of OSIRIS data reduction that are
relevant to the next generation of integral field spectrograph hardware and
data reduction software design.Comment: 18 pages, 16 figures; accepted for publication in A