185 research outputs found
Distance to Multiple Kinematic Components of Quasar Outflows: VLT Observations of QSO 2359-1241 and SDSS J0318-0600
Using high resolution VLT spectra, we study the multi-component outflow
systems of two quasars exhibiting intrinsic Fe II absorption (QSO 2359-1241 and
SDSS J0318-0600). From the extracted ionic column densities and using
photoionization modeling we determine the gas density, total column density,
and ionization parameter for several of the components. For each object the
largest column density component is also the densest, and all other components
have densities of roughly 1/4 of that of the main component. We demonstrate
that all the absorbers lie roughly at the same distance from the source.
Further, we calculate the total kinetic luminosities and mass outflow rates of
all components and show that these quantities are dominated by the main
absorption component.Comment: 27 pages, 5 figure
BAL Outflow Contribution to AGN Feedback: Frequency of S iv Outflows in the SDSS
We present a study of Broad Absorption Line (BAL) quasar outflows that show S
IV ?1063 and S IV* ?1073 troughs. The fractional abundance of S IV and C IV
peak at similar value of the ionization parameter, implying that they arise
from the same physical component of the outflow. Detection of the S IV* troughs
will allow us to determine the distance to this gas with higher resolution and
higher signal-to-noise spectra, therefore providing the distance and energetics
of the ubiquitous C IV BAL outflows. In our bright sample of 156 SDSS quasars
14% show C IV and 1.9% S IV troughs, which is consistent with a fainter
magnitude sample with twice as many objects. One object in the fainter sample
shows evidence of a broad S IV trough without any significant trough present
from the excited state line, which implies that this outflow could be at a
distance of several kpc. Given the fractions of C IV and S IV, we establish
firm limits on the global covering factor on S IV that ranges from 2.8% to 21%
(allowing for the k-correction). Comparison of the expected optical depth for
these ions with their detected percentage suggests that these species arise
from common outflows with a covering factor closer to the latter.Comment: Published in ApJ (2012 ApJ, 750, 143
Determining the Locations of Dust Sources in FeLoBAL Quasars
We conduct a spectroscopic search of quasars observed by the Sloan Digital
Sky Survey (SDSS) with broad absorption line (BAL) troughs due to Mg II and
troughs due to Fe II that simultaneously exhibit strong Balmer narrow emission
lines (NELs). We find that in a redshift range of 0.4 less than or equal to z
less than or equal to 0.9 approximately 23 of the 70 Mg II BALs and 4 of a
subset of 15 Fe II BALs exhibit strong Balmer emission. We also find
significant fractions of Mg II BALs (approximately 23%) and those Mg II BALs
with Fe II troughs (approximately 27%) have strong continuum reddening, E(B -
V) greater than or equal to 0.1. From measurements of the Balmer decrement in
three objects, we find similarly significant reddening of the NEL region in
three of the four objects; the NELs in the fourth object are not measurable. We
also include one object in this study not taken from the SDSS sample that shows
Fe II absorption and strong narrow emission, but due to measurement uncertainty
and low continuum reddening the comparison is consistent but inconclusive. We
find a trend in both the Mg II and Fe II BAL samples between the NEL reddening
and continuum reddening. Because the narrow line reddening is consistent with
the continuum reddening in every object in the two SDSS samples, it suggests
that the reddening sources in these objects likely exist at larger radial
distances than the narrow line regions from the central nucleus.Comment: 40 manuscript pages, accepted in ApJ (July
The Quasar Outflow Contribution to AGN Feedback: VLT Measurements of SDSS J0318-0600
We present high spectral resolution VLT observations of the BAL quasar SDSS
J0318-0600. This high quality data set allows us to extract accurate ionic
column densities and determine an electron number density of n_e=10^3.3 +/- 0.2
cm^-3 for the main outflow absorption component. The heavily reddened spectrum
of SDSS J0318-0600 requires purely silicate dust with a reddening curve
characteristic of predominately large grains, from which we estimate the
bolometric luminosity. We carry out photoionization modeling to determine the
total column density, ionization parameter and distance of the gas and find
that the photionization models suggest abundances greater than solar. Due to
the uncertainty in the location of the dust extinction, we arrive at two viable
distances for the main ouflow component from the central source, 6 and 18 kpc,
where we consider the 6 kpc location as somewhat more physically plausable.
Assuming the canonical global covering of 20% for the outflow and a distance of
6 kpc, our analysis yields a mass flux of 120 M_sun yr^-1 and a kinetic
luminosity that is ~0.1% of the bolometric luminosity of the object. Should the
dust be part of the outflow, then these values are ~4x larger. The large mass
flux and kinetic luminosity make this outflow a significant contributor to AGN
feedback processes.Comment: Accepted for publication in ApJ, 57 pages, 14 figure
TCR-engineered adoptive cell therapy effectively treats intracranial murine glioblastoma
BACKGROUND: Adoptive cellular therapies with chimeric antigen receptor T cells have revolutionized the treatment of some malignancies but have shown limited efficacy in solid tumors such as glioblastoma and face a scarcity of safe therapeutic targets. As an alternative, T cell receptor (TCR)-engineered cellular therapy against tumor-specific neoantigens has generated significant excitement, but there exist no preclinical systems to rigorously model this approach in glioblastoma.
METHODS: We employed single-cell PCR to isolate a TCR specific for the Imp3
RESULTS: We isolated and characterized the 3×1.1C TCR that displayed a high affinity for mImp3 but no wild-type cross-reactivity. To provide a source of mImp3-specific T cells, we generated the MISTIC mouse. In a model of adoptive cellular therapy, the infusion of activated MISTIC T cells resulted in rapid intratumoral infiltration and profound antitumor effects with long-term cures in a majority of GL261-bearing mice. The subset of mice that did not respond to the adoptive cell therapy showed evidence of retained neoantigen expression but intratumoral MISTIC T cell dysfunction. The efficacy of MISTIC T cell therapy was lost in mice bearing a tumor with heterogeneous mImp3 expression, showcasing the barriers to targeted therapy in polyclonal human tumors.
CONCLUSIONS: We generated and characterized the first TCR transgenic against an endogenous neoantigen within a preclinical glioma model and demonstrated the therapeutic potential of adoptively transferred neoantigen-specific T cells. The MISTIC mouse provides a powerful novel platform for basic and translational studies of antitumor T-cell responses in glioblastoma
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