909 research outputs found
Constraints on the environment and energetics of the Broad-Line Ic SN2014ad from deep radio and X-ray observations
Broad-line type Ic Supernovae (BL-Ic SNe) are characterized by high ejecta
velocity ( km s) and are sometimes associated with the
relativistic jets typical of long duration ( s) Gamma-Ray Bursts
(L-GRBs). The reason why a small fraction of BL-Ic SNe harbor relativistic jets
is not known. Here we present deep X-ray and radio observations of the BL-Ic
SN2014ad extending from to days post explosion. SN2014ad was not
detected at either frequency and has no observational evidence of a GRB
counterpart. The proximity of SN2014ad ( Mpc) enables very deep
constraints on the progenitor mass-loss rate and on the total energy
of the fast ejecta . We consider two synchrotron emission scenarios for a
wind-like circumstellar medium (CSM): (i) uncollimated non-relativistic ejecta,
and (ii) off-axis relativistic jet. Within the first scenario our observations
are consistent with GRB-less BL-Ic SNe characterized by a modest energy budget
of their fast ejecta ( erg), like SNe 2002ap and 2010ay.
For jetted explosions, we cannot rule out a GRB with erg
(beam-corrected) with a narrow opening angle ()
observed moderately off-axis () and
expanding in a very low CSM density ( M
yr). Our study shows that off-axis low-energy jets expanding in a
low-density medium cannot be ruled out even in the most nearby BL-Ic SNe with
extensive deep observations, and might be a common feature of BL-Ic SNe.Comment: 9 pages, 5 figures, accepted in Ap
Effect of fertilizer levels on nutrient availability and yield of cotton on Vertisol at Rahuri, District Ahemadnagar, India
The field experiment on effect of fertilizer levels on nutrient availability and yield of cotton on Vertisol was conducted at Mahatma Phule Krishi Vidyapeeth, Rahuri during May to September, 2008. The experiment was laid out in factorial randomized block design with three replications and two main treatments i.e. hybrid Bt RCH-2 and Non-Bt RCH-2 and nine sub treatments with different fertilizer doses i.e. F1 - No recommended doses of fertilizer (RDF), F2 -50 % RDF, F3 - 75 % RDF, F4 - 100 % RDF, F5 -125 % RDF, F6 - 150 % RDF, F7 - 100 % RDF + 2% DAP spray, F8 -100 % RDF + 1 % MgSO4 and F9 -100 % RDF + 1% KNO3. The results revealed that the non-Bt hybrid recorded maximum nitrogen (435.67 kg ha-1) and potassium (565.45 kg ha-1) content in 100 % RDF + 1% KNO3 treatment at boll development stage as compared to Bt hybrid. However, magnesium (0.09 kg ha-1) and iron (3.66 ppm) were maximum in 100 % RDF + 1 % MgSO4 treatment in non-Bt as compared to Bt hybrid and phosphorus content (17.58 kg ha-1) was maximum in 100 % RDF + 2 % DAP treatment in Bt as compared to non-Bt hybrid at boll development stage. The application of 100 % RDF + 1 % MgSO4 sprays were recorded highest yield of Bt (33.53 q ha-1) and non-Bt cotton hybrids (31.27 q ha-1)
GRB 030329: 3 years of radio afterglow monitoring
Radio observations of gamma-ray burst (GRB) afterglows are essential for our
understanding of the physics of relativistic blast waves, as they enable us to
follow the evolution of GRB explosions much longer than the afterglows in any
other wave band. We have performed a three-year monitoring campaign of GRB
030329 with the Westerbork Synthesis Radio Telescopes (WSRT) and the Giant
Metrewave Radio Telescope (GMRT). Our observations, combined with observations
at other wavelengths, have allowed us to determine the GRB blast wave physical
parameters, such as the total burst energy and the ambient medium density, as
well as investigate the jet nature of the relativistic outflow. Further, by
modeling the late-time radio light curve of GRB 030329, we predict that the
Low-Frequency Array (LOFAR, 30-240 MHz) will be able to observe afterglows of
similar GRBs, and constrain the physics of the blast wave during its
non-relativistic phase.Comment: 5 pages, 2 figures, Phil. Trans. R. Soc. A, vol.365, p.1241,
proceedings of the Royal Society Scientific Discussion Meeting, London,
September 200
Evaluation of percutaneous pinning in fracture proximal one-third humerus and fracture dislocation
Background: Proximal humerus fracture treatment is still an issue with lot of controversies and various treatment modalities had yielded mixed results. Our aim is to study percutaneous K-wires fixation as a modality of treatment, does not need extensive soft tissue dissection, so small fracture fragments & retains periosteal muscle & ligament attachments which held the fracture fragments together. Complications of open reduction are avoided.Methods: Fractures were classified according to Neer’s Classification system and were treated with closed reduction and K-wire Fixation. They were 16 males and 09 females, with a mean age of 40.5 years. Mean follow-up was of 20.5 months (range 9-24 months). Post-operative mean VAS score and Constant Score of patients was 2.1 (±0.73) and 78.1 (±9.61) at an average follow up of 6 months. Mean duration for union was 6.5 (±1.18) weeks. Patients were followed up at 4, 8, 12 weeks and 3, 6, 9 & 12 months interval.Results: Radiological and functional outcome assessed according to Constant-Murley Shoulder assessment. Complications treated accordingly. Percutaneous K-wire fixation is safe, limited invasive technique and following basic principles of anatomical reduction has excellent results & functional outcome.Conclusions: We concluded that the soft-tissue bridging of the fracture fragments was crucial for the reduction to benefit from the ligamentotaxis effect. This technique worked well for valgus-impacted or three-part fractures. The rate of osteonecrosis was low, and rehabilitation was easier. Overall, the results from these series are quite encouraging
Relativistic supernovae have shorter-lived central engines or more extended progenitors: the case of SN\,2012ap
Deep late-time X-ray observations of the relativistic, engine-driven, type Ic
SN2012ap allow us to probe the nearby environment of the explosion and reveal
the unique properties of relativistic SNe. We find that on a local scale of
~0.01 pc the environment was shaped directly by the evolution of the progenitor
star with a pre-explosion mass-loss rate <5x10^-6 Msun yr-1 in line with GRBs
and the other relativistic SN2009bb. Like sub-energetic GRBs, SN2012ap is
characterized by a bright radio emission and evidence for mildly relativistic
ejecta. However, its late time (t~20 days) X-ray emission is ~100 times fainter
than the faintest sub-energetic GRB at the same epoch, with no evidence for
late-time central engine activity. These results support theoretical proposals
that link relativistic SNe like 2009bb and 2012ap with the weakest observed
engine-driven explosions, where the jet barely fails to breakout. Furthermore,
our observations demonstrate that the difference between relativistic SNe and
sub-energetic GRBs is intrinsic and not due to line-of-sight effects. This
phenomenology can either be due to an intrinsically shorter-lived engine or to
a more extended progenitor in relativistic SNe.Comment: Version accepted to ApJ. Significantly broadened discussio
iPTF15eqv: Multi-wavelength Expos\'e of a Peculiar Calcium-rich Transient
The progenitor systems of the class of "Ca-rich transients" is a key open
issue in time domain astrophysics. These intriguing objects exhibit unusually
strong calcium line emissions months after explosion, fall within an
intermediate luminosity range, are often found at large projected distances
from their host galaxies, and may play a vital role in enriching galaxies and
the intergalactic medium. Here we present multi-wavelength observations of
iPTF15eqv in NGC 3430, which exhibits a unique combination of properties that
bridge those observed in Ca-rich transients and Type Ib/c supernovae. iPTF15eqv
has among the highest [Ca II]/[O I] emission line ratios observed to date, yet
is more luminous and decays more slowly than other Ca-rich transients. Optical
and near-infrared photometry and spectroscopy reveal signatures consistent with
the supernova explosion of a < 10 solar mass star that was stripped of its
H-rich envelope via binary interaction. Distinct chemical abundances and ejecta
kinematics suggest that the core collapse occurred through electron capture
processes. Deep limits on possible radio emission made with the Jansky Very
Large Array imply a clean environment ( 0.1 cm) within a radius of
cm. Chandra X-ray Observatory observations rule out alternative
scenarios involving tidal disruption of a white dwarf by a black hole, for
masses > 100 solar masses). Our results challenge the notion that
spectroscopically classified Ca-rich transients only originate from white dwarf
progenitor systems, complicate the view that they are all associated with large
ejection velocities, and indicate that their chemical abundances may vary
widely between events.Comment: 24 pages, 16 figures. Closely matches version published in The
Astrophysical Journa
Pure red cell aplasia (PRCA) following ABO-incompatible allogeneic bone marrow transplantation
- …