Wyithe, Stuart, Hopkins, Andrew M., Kistler, Matthew D., Yuksel, Hasan, Beacom, John F.
The fraction of ionizing photons that escape their host galaxies and so are able to ionize hydrogen in the inter-galactic medium (IGM) is a critical parameter in analyses of the reionization era and...
The Star Formation Rate in the Reionization Era as Indicated by Gamma-ray Bursts (2009)
Kistler, Matthew D., Yuksel, Hasan, Beacom, John F., Hopkins, Andrew M., Wyithe, J. Stuart B.
High-redshift gamma-ray bursts (GRBs) offer an extraordinary opportunity to study aspects of the early Universe, including the cosmic star formation rate (SFR). Motivated by the two recent highest-z...
CMSSM Spectroscopy in light of PAMELA and ATIC (2009)
Gogoladze, Ilia, Khalid, Rizwan, Shafi, Qaisar, Yuksel, Hasan
Dark matter neutralinos in the constrained minimal supersymmetric model (CMSSM) may account for the recent cosmic ray electron and positron observations reported by the PAMELA and ATIC experiments...
TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess (2008)
Yuksel, Hasan, Kistler, Matthew D., Stanev, Todor
The Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray point sources. We examine the implications of the recent Milagro detection of extended, multi-TeV gamma-ray emission from...
Core-Collapse Astrophysics with a Five-Megaton Neutrino Detector (2008)
Kistler, Matthew D., Yuksel, Hasan, Ando, Shin'ichiro, Beacom, John F., Suzuki, Yoichiro
The legacy of solar neutrinos suggests that large neutrino detectors should be sited underground. However, to instead go underwater bypasses the need to move mountains, allowing much larger contained...
Revealing the High-Redshift Star Formation Rate with Gamma-Ray Bursts (2008)
Yuksel, Hasan, Kistler, Matthew D., Beacom, John F., Hopkins, Andrew M.
While the high-z frontier of star formation rate (SFR) studies has advanced rapidly, direct measurements beyond z ~ 4 remain difficult, as shown by significant disagreements among different results....
Conservative Constraints on Dark Matter Annihilation into Gamma Rays (2008)
Mack, Gregory D., Jacques, Thomas D., Beacom, John F., Bell, Nicole F., Yuksel, Hasan
Using gamma-ray data from observations of the Milky Way, Andromeda (M31), and the cosmic background, we calculate conservative upper limits on the dark matter self-annihilation cross section to...
Circumscribing Late Dark Matter Decays Model Independently (2007)
Yuksel, Hasan, Kistler, Matthew D.
A number of theories, spanning a wide range of mass scales, predict dark matter candidates that have lifetimes much longer than the age of the universe, yet may produce a significant flux of gamma...
An Unexpectedly Swift Rise in the Gamma-ray Burst Rate (2007)
Kistler, Matthew D., Yuksel, Hasan, Beacom, John F., Stanek, Krzysztof Z.
The association of long gamma-ray bursts with supernovae naturally suggests that the cosmic GRB rate should trace the star formation history. Finding otherwise would provide important clues...
Neutrino Constraints on the Dark Matter Total Annihilation Cross Section (2007)
Yuksel, Hasan, Horiuchi, Shunsaku, Beacom, John F., Ando, Shin'ichiro
In the indirect detection of dark matter through its annihilation products, the signals depend on the square of the dark matter density, making precise knowledge of the distribution of dark matter in...
Strong Upper Limits on Sterile Neutrino Warm Dark Matter (2007)
Yuksel, Hasan, Beacom, John F., Watson, Casey R.
Sterile neutrinos are attractive dark matter candidates. Their parameter space of mass and mixing angle has not yet been fully tested despite intensive efforts that exploit their gravitational...
Neutrino Spectrum from SN 1987A and from Cosmic Supernovae (2007)
Yuksel, Hasan, Beacom, John F.
The detection of neutrinos from SN 1987A by the Kamiokande-II and Irvine-Michigan-Brookhaven detectors provided the first glimpse of core collapse in a supernova, complementing the optical...
Enhanced Cosmological GRB Rates and Implications for Cosmogenic Neutrinos (2006)
Yuksel, Hasan, Kistler, Matthew D.
Gamma-ray bursts, which are among the most violent events in the universe, are one of the few viable candidates to produce ultrahigh energy cosmic rays. Recently, observations have revealed that GRBs...
Yuksel, Hasan, Ozbilgin, Kemal, Coskun, Senol, Tuglu, Ibrahim
Increased activation of alveolar macrophage, neutrophil and mast cell has been proven in cigarette smoking (CS)-related lung disorders (CSLD). An increased production of cysteinyl-leukotrienes (LTs),...
Coskun, Senol, Yuksel, Hasan, Bilgi, Yasar, Lacin, Selman, Tansug, Nermin, Onag, Ali
Postnatal adaptations of cardiac hemodynamics in infants born vaginally or by caesarean section may be different. These cardiac functions were evaluated by Doppler echocardiography to assess...
Positron Annihilations at the Galactic Center: Generating More Questions Than Answers (2006)
The bulge of our Galaxy is illuminated by the 0.511 MeV gamma-ray line flux from annihilations of nonrelativistic positrons. The emission is strongly concentrated at the Galactic Center, in contrast...
Direct X-ray Constraints on Sterile Neutrino Warm Dark Matter (2006)
Watson, Casey R., Beacom, John F., Yuksel, Hasan, Walker, Terry P.
Warm dark matter (WDM) might more easily account for small scale clustering measurements than the heavier particles typically invoked in Lambda cold dark matter (LCDM) cosmologies. In this paper, we...
Stringent Constraint on Galactic Positron Production (2005)
Beacom, John F., Yuksel, Hasan
The intense 0.511 MeV gamma-ray line emission from the Galactic Center observed by INTEGRAL requires a large annihilation rate of nonrelativistic positrons. If these positrons are injected at even...
Yuksel, Hasan, Ando, Shin'ichiro, Beacom, John
The time-integrated luminosity and average energy of the neutrino emission spectrum are essential diagnostics of core-collapse supernovae. The SN 1987A electron antineutrino observations by the...
Ertug, Sema, Okyay, Pinar, Turkmen, Munevver, Yuksel, Hasan
Abstract Background The aims of the present study were to determine the prevalence of toxoplasmosis in pregnant women at first trimester of their pregnancy and to follow up the seroconversion for...
Detection of Neutrinos from Supernovae in Nearby Galaxies (2005)
Ando, Shin'ichiro, Beacom, John F., Yuksel, Hasan
While existing detectors would see a burst of many neutrinos from a Milky Way supernova, the supernova rate is only a few per century. As an alternative, we propose the detection of ~ 1 neutrino per...