18,253 research outputs found
Do Anomalous Narrow Line Quasars Cast Doubt on Virial Mass Estimation?
Anomalous Narrow-Line Quasars (ANLs) are a population of quasars with narrow
H\beta, and sometimes [O III] broader than ~1000 km/s, in total comprising \sim
10-30% (most likely ~25%) of Type I quasars at 0.2 < z < 0.8. We find that
virial masses using the H\beta and Mg II lines systematically differ for ANLs
by an average of as much as 0.5 dex. Because the broad H\beta component width
increases in ANLs but Mg II does not, we might suspect H\beta-based virial
masses for ANLs are wrong but Mg II masses are correct. If this is due to an
outflow reaching the lower-ionization potential H\beta line, C IV masses will
be similarly flawed. However, we cannot be certain of this explanation without
followup work, and may be unable to identify which quasars are ANLs at z > 0.8.
Therefore, it is essential that ANLs be well-understood and well-modeled in
order to allow the use of virial mass estimators on large optical spectroscopic
catalogs, particularly at z 2.0 where only one broad line is
available for use in mass estimation.Comment: 5 pages, submitte
Star formation in galaxies hosting Active Galactic Nuclei up to z~1
We review recent evidence for a clear association between accretion onto
supermassive black holes and star formation up to z~1 in the zCOSMOS survey.
Star formation rates (SFRs) are determined from the [OII] emission-line
strength and a correction for the AGN contribution. We find that SFRs of X-ray
selected AGN span a distribution of 1-100 solar masses per year and evolve in a
manner that is indistinguishable from that of massive, star-forming galaxies.
The close relationship between AGN activity and star formation is further
supported by an increase in the AGN fraction with bluer rest-frame colors
(U-V); we further illustrate how the location of AGNs in a color-magnitude
diagram can be misleading in luminosity-limited samples due to the dependence
of AGN activity on the stellar mass and the low mass-to-light ratios of blue
cloud galaxies. To conclude, our results support a co-evolutionary scenario up
to z~1 based on the constancy with redshift of the ratio between mass accretion
rate and SFR.Comment: Invited talk, to appear in the Proceedings of "AGN Feedback in Galaxy
Formation", V.Antonuccio-Delogu and J. Silk, eds., in pres
Spatial Corrections of ROSAT HRI Observations
X-ray observations with the ROSAT High Resolution Imager (HRI) often have
spatial smearing on the order of 10 arcsec (Morse 1994). This degradation of
the intrinsic resolution of the instrument (5 arcsec) can be attributed to
errors in the aspect solution associated with the wobble of the space craft or
with the reacquisition of the guide stars. We have developed a set of IRAF/PROS
and MIDAS/EXSAS routines to minimize these effects. Our procedure attempts to
isolate aspect errors that are repeated through each cycle of the wobble. The
method assigns a 'wobble phase' to each event based on the 402 second period of
the ROSAT wobble. The observation is grouped into a number of phase bins and a
centroid is calculated for each sub-image. The corrected HRI event list is
reconstructed by adding the sub-images which have been shifted to a common
source position. This method has shown approx. 30% reduction of the full width
half maximum (FWHM) of an X-ray observation of the radio galaxy 3C 120.
Additional examples are presented.Comment: AandA latex (6 pages with 7 embedded postscript figures). Scheduled
for publication in the 1 Dec issue of Astron. Astrophys. Suppl. Serie
Innovations in Opioid Law and Policy Interventions Workshop: Summary of Proceedings
In 2017, Indiana University, in cooperation with Indiana Governor Eric Holcomb and community partners, launched the Grand Challenge: Responding to the Addictions Crisis initiative, a university-wide effort to advance interdisciplinary research and interventions in response to the substance abuse crisis affecting Indiana and the nation. The “Legal and Policy Best Practices in Response to the Substance Abuse Crisis” project is one of sixteen funded under Phase 1 of the Grand Challenge.
In July 2018, and as part of this project, the research team convened a group of national experts to discuss legal and policy innovations to respond to the opioid use disorder (OUD) crisis. This report summarizes the proceedings of this workshop and updates some of the recommendations made by the team in their March 2018 Preliminary Report.
During the workshop, experts answered targeted questions relating to the challenges in implementing law and policy recommendations to respond to the addiction crisis, as well as identified gaps in the current research. Participants provided examples of innovative interventions to respond to this crisis across four primary topic categories: (1) Criminalization; (2) Public Health; (3) Treatment; and (4) Effectuating Change
Single-stage, low-noise, advanced technology fan. Volume 4: Fan aerodynamics. Section 1: Results and analysis
Test results at design speed show fan total pressure ratio, weight flow, and adiabatic efficiency to be 2.2, 2.9, and 1.8% lower than design goal values. The hybrid acoustic inlet (which utilizes a high throat Mach number and acoustic wall treatment for noise suppression) demonstrated total pressure recoveries of 98.9% and 98.2% at takeoff and approach. Exhaust duct pressure losses differed between the hardwall duct and treated duct with splitter by about 0.6% to 2.0% in terms of fan exit average total pressure (depending on operating condition). When the measured results were used to estimate pressure losses, a cruise sfc penalty of 0.68%, due to the acoustically treated duct, was projected
Study of explosions in the NASA-MSC Vibration and Acoustic Test Facility /VATF/ Final report
Damage potential of titanium alloy pressure spheres relative to spacecraft vibration testin
Ionization Mechanisms in Jet-Dominated Seyferts: A Detailed Case Study
For the past 10 years there has been an active debate over whether fast
shocks play an important role in ionizing emission line regions in Seyfert
galaxies. To investigate this claim, we have studied the Seyfert 2 galaxy Mkn
78, using HST UV/optical images and spectroscopy. Since Mkn 78 provides the
archetypal jet-driven bipolar velocity field, if shocks are important anywhere
they should be important in this object. Having mapped the emission line fluxes
and velocity field, we first compare the ionization conditions to standard
photoionization and shock models. We find coherent variations of ionization
consistent with photoionization model sequences which combine optically thick
and thin gas, but are inconsistent with either autoionizing shock models or
photoionization models of just optically thick gas. Furthermore, we find
absolutely no link between the ionization of the gas and its kinematic state,
while we do find a simple decline of ionization degree with radius. We feel
this object provides the strongest case to date against the importance of shock
related ionization in Seyferts.Comment: 4 pages, 1 figure, to appear in the proceedings of IAU Symposium 222
"The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", T.
Storchi Bergmann, L.C. Ho & H.R. Schmitt, ed
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