85 research outputs found
The Powerful Jet and Gamma-Ray Flare of the Quasar PKS 0438436
PKS 0438436 at a redshift of has been previously recognized as
possessing perhaps the most luminous known synchrotron jet. Little is known
about this source since the maximum elevation above the horizon is low for the
Very Large Array (VLA). We present the first VLA radio image that detects the
radio lobes. We use both the 151 MHz luminosity, as a surrogate for the
isotropic radio lobe luminosity, and the lobe flux density from the radio image
to estimate a long term, time averaged, jet power, . We analyze two deep optical spectra with
strong broad emission lines and estimate the thermal bolometric luminosity of
the accretion flow, . The ratio, , is at
the limit of this empirical metric of jet dominance seen in radio loud quasars
and this is the most luminous accretion flow to have this limiting behavior.
Despite being a very luminous blazar, it previously had no -ray
detections (EGRET, AGILE or FERMI) until December 11 - 13 2016 (54 hours) when
FERMI detected a flare that we analyze here. The isotropic apparent luminosity
from 100 MeV - 100 GeV rivals the most luminous detected blazar flares
(averaged over 18 hours), . The
-ray luminosity varies over time by two orders of magnitude,
highlighting the extreme role of Doppler abberation and geometric alignment in
producing the inverse Compton emission.Comment: To appear in ApJ. Revision required to replace the last figure file
with the current versio
Looking for Signatures of AGN Feedback in Radio-Quiet AGN
(Abridged) In this article, we discuss the state of ``AGN feedback'' in
radio-quiet (RQ) AGN. This study involves heterogeneous samples of nearby
Seyfert and LINER galaxies as well as QSOs that have been observed at low radio
frequencies (few ~100 MHz) with the GMRT and ~GHz frequencies with the VLA and
VLBA. These multi-frequency, multi-resolution observations detect a range of
arcsecond-scale radio spectral indices that are consistent with the presence of
multiple contributors including starburst winds and AGN jets or winds; steep
spectrum ``relic'' emission is observed as well. Polarization-sensitive data
from the VLA and GMRT suggest that the radio outflows are stratified (e.g., in
IIIZw2, Mrk231); distinct polarization signatures suggest that there could
either be a ``spine + sheath'' structure in the radio outflow, or there could
be a ``jet + wind'' structure. Similar nested biconical outflows can also
explain the VLBA and SDSS emission-line data in the KISSR sample of
double-peaked emission-line Seyfert and LINER galaxies. Furthermore, the
modeling of the emission-lines with plasma modeling codes such as MAPPINGS
indicates that parsec-scale jets and winds in these sources can disturb or move
the narrow-line region gas clouds via the ``shock + precursor'' mechanism.
Apart from the presence of ``relic'' emission, several Seyfert and LINER
galaxies show clear morphological signatures of episodic jet activity. In one
such source, NGC2639, at least four distinct episodes of jets are observed, the
largest one of which was only detectable at 735 MHz with the GMRT.
Additionally, a ~6 kpc hole in the CO molecular gas along with a dearth of
young stars in the center of its host galaxy is observed. This suggests a link
between episodic jet activity in RQ AGN and ``AGN feedback'' influencing the
evolution of their host galaxies.Comment: 20 pages, 5 figures, Invited review for Galaxies Special Issue "The
Symbiosis between Radio Source and Galaxy Evolution
The Extreme Ultraviolet Deficit - Jet Connection in the Quasar 1442+101
In previous studies, it has been shown that the long term time average jet
power, , is correlated with the spectral index in the extreme
ultraviolet (EUV), (defined by computed between 700\AA\, and 1100\AA\,). Larger
tends to decrease the EUV emission. This is a curious
relationship because it connects a long term average over years
with an instantaneous measurement of the EUV. The EUV appears to be emitted
adjacent to the central supermassive black hole and the most straightforward
explanation of the correlation is that the EUV emitting region interacts in
real time with the jet launching mechanism. Alternatively stated, the
- correlation is a manifestation of a
contemporaneous (real time) jet power, , correlation with .
In order to explore this possibility, this paper considers the time variability
of the strong radio jet of the quasar 1442+101 that is not aberrated by strong
Doppler enhancement. This high redshift (z = 3.55) quasar is uniquely suited
for this endeavor as the EUV is redshifted into the optical observing window
allowing for convenient monitoring. More importantly, it is bright enough to be
seen through the Lyman forest and its radio flux is strong enough that it has
been monitored frequently. Quasi-simultaneous monitoring (five epochs spanning
years) show that increases in correspond to decreases in the
EUV as expected.Comment: To appear in Ap
An evaluation of adverse drug reactions monitoring at a pharmacovigilance unit under pharmacovigilance program of India in a tertiary care hospital of Haryana
Background: Adverse drug reactions (ADRs) are among top 10 causes of mortality in patients. Pharmacovigilance programme of India (PvPI) is a step towards participation in the WHO programme for International Drug Safety Monitoring. The present article is an evaluation of the incidence and the patterns of ADRs from the reports collected from various clinical departments of this hospital.Methods: A total of 859 suspected ADR reports submitted to the pharmacovigilance unit at Department of Pharmacology under PvPI were evaluated for 6 months with respect to demographics, causative drug, organ system involvement, severity and seriousness of ADRs. The causality assessment was carried out by using WHO assessment method and Naranjo’s scale.Results: Males experienced more (66.33%) ADRs. The highest percentage (45.83%) of ADRs was seen in the age group of 46-60 years (35.33%), followed by 16-30 years (25.5%). The most common drug group causing ADRs was antimicrobials (43.37%), followed by anticancer and immunosuppressive agents (29.02%). The gastrointestinal system (31.43%) was most prone system, followed by generalized body reactions (22.93%) and cutaneous reactions (17.11%). 662 (77%) ADRs were non-serious, 197 (22.9%) were serious. On severity scale, 682 (79.39%) were mild, 168 (19.65%) moderate and only 9 (1.05%) ADRs were severe out of which three were fatal. As per WHO assessment method 66.94% ADRs were probable and 33.06% possible. The probability was comparable with Naranjo’s scale.Conclusion: ADRs to drugs happen commonly, and their reporting is important for the early recognition and prevention of ADRs and will also help in generating signals. ADR monitoring not only acts as an alerting mechanism for physicians, but helps the regulatory authorities in making the policy decision
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