338 research outputs found
A Search for Early Optical Emission from Short and Long Duration Gamma-ray Bursts
Gamma-ray bursts of short duration may harbor vital clues to the range of
phenomena producing bursts. However, recent progress from the observation of
optical counterparts has not benefitted the study of short bursts. We have
searched for early optical emission from six gamma-ray bursts using the ROTSE-I
telephoto array. Three of these events were of short duration, including GRB
980527 which is among the brightest short bursts yet observed. The data consist
of unfiltered CCD optical images taken in response to BATSE triggers delivered
via the GCN. For the first time, we have analyzed the entire 16 degree by 16
degree field covered for five of these bursts. In addition, we discuss a search
for the optical counterpart to GRB 000201, a well-localized long burst. Single
image sensitivities range from 13th to 14th magnitude around 10 s after the
initial burst detection, and 14 - 15.8 one hour later. No new optical
counterparts were discovered in this analysis suggesting short burst optical
and gamma-ray fluxes are uncorrelated.Comment: 8 pages, 2 figures, subm. to ApJ Let
Prompt Optical Observations of Gamma-ray Bursts
The Robotic Optical Transient Search Experiment (ROTSE) seeks to measure
simultaneous and early afterglow optical emission from gamma-ray bursts (GRBs).
A search for optical counterparts to six GRBs with localization errors of 1
square degree or better produced no detections. The earliest limiting
sensitivity is m(ROTSE) > 13.1 at 10.85 seconds (5 second exposure) after the
gamma-ray rise, and the best limit is m(ROTSE) > 16.0 at 62 minutes (897 second
exposure). These are the most stringent limits obtained for GRB optical
counterpart brightness in the first hour after the burst. Consideration of the
gamma-ray fluence and peak flux for these bursts and for GRB990123 indicates
that there is not a strong positive correlation between optical flux and
gamma-ray emission.Comment: 4 pages, 3 figures, submitted to ApJ Letter
The Cosmology of String Theoretic Axions
String theory posesses numerous axion candidates. The recent realization that
the compactification radius in string theory might be large means that these
states can solve the strong CP problem. This still leaves the question of the
cosmological bound on the axion mass. Here we explore two schemes for
accommodating such light axions in cosmology. In the first, we note that in
string theory the universe is likely to be dominated early on by the coherent
oscillations of some moduli. The usual moduli problem assumes that these fields
have masses comparable to the gravitino. We argue that string moduli are likely
to be substantially more massive, eliminating this problem. In such cosmologies
the axion bound is significantly weakened. Plausible mechanisms for generating
the baryon number density are described. In the second, we point out that in
string theory, the axion potentials might be much larger at early times than at
present. In string theory, if CP violation is described by a small parameter,
the axion may sit sufficiently close to its true minimum to invalidate the
bounds.Comment: 24 pages, uses harvmac. Refs corrected plus spellin
The Case for a Muon Collider Higgs Factory
We propose the construction of a compact Muon Collider Higgs Factory. Such a
machine can produce up to \sim 14,000 at 8\times 10^{31} cm^-2 sec^-1 clean
Higgs events per year, enabling the most precise possible measurement of the
mass, width and Higgs-Yukawa coupling constants.Comment: Supporting letter for the document: "Muon Collider Higgs Factory for
Smowmass 2013", A White Paper submitted to the 2013 U.S. Community Summer
Study of the Division of Particles and Fields of the American Physical
Society, Y. Alexahin, et. al, FERMILAB-CONF-13-245-T (July, 2013
The Vehicle, Fall 1986
Table of Contents
Selling Poetry: Honesty with the InvestorPatrick Peterspage 2
Father\u27s Book, Jan. 1984 (A Fictional Autobiography)James T. Finneganpage 3
Pet Day in Afternoon KindergartenDan Von Holtenpage 7
Dental Dreams in the Bathroom MirrorDan Von Holtenpage 7
PhotographStephanie Eihlpage 8
SilenceJoe Hortonpage 8
SkullMichael Salempage 9
The TunnelJim Harrispage 10
Lindenwood CemeteryJean Chandlerpage 12
Into the SeaDan Seltzerpage 13
PhotographStephanie Eihlpage 13
WindowsJim Harrispage 14
Little Pieces of YouStuart Albertpage 18
Slicing the AppleAmy Callpage 19
Winter WalkLarry Mitchellpage 19
Komical KellyJohn Fehrmannpage 20
Thermal SueJohn Fehrmannpage 20
Death PoemBob Zordanipage 21
Venice, ItalySherry L. Clinepage 22
RoadkillPhil Simpsonpage 24
I Hate CowsLori Delzer, Joe Crites, Becky Michaelpage 32
Telephone Operators: 1942Jim Harrispage 33
Expiration Date 3/8/65Edward Schellpage 34
Desert FloorPatrick Peterspage 35
PhotographLawrence McGownpage 36
PhotographStephanie Eihlpage 37
Coping with NightStuart Albertpage 38
PhotographDan Mountpage 38
One On OnePatrick Peterspage 39
An Acquired TasteTina Wrightpage 40
PhotographStephanie Eihlpage 40
PhotographStephanie Eihlpage 41
When Children Are Alone, The Devil SpeaksTom Greenpage 41
BobChristy Denphypage 42
Gut & ScissorsDane Buczkowskipage 42
This Old HouseAmy Callpage 43
MortgageTina Wrightpage 43https://thekeep.eiu.edu/vehicle/1048/thumbnail.jp
The Vehicle, Fall 1986
Table of Contents
Selling Poetry: Honesty with the InvestorPatrick Peterspage 2
Father\u27s Book, Jan. 1984 (A Fictional Autobiography)James T. Finneganpage 3
Pet Day in Afternoon KindergartenDan Von Holtenpage 7
Dental Dreams in the Bathroom MirrorDan Von Holtenpage 7
PhotographStephanie Eihlpage 8
SilenceJoe Hortonpage 8
SkullMichael Salempage 9
The TunnelJim Harrispage 10
Lindenwood CemeteryJean Chandlerpage 12
Into the SeaDan Seltzerpage 13
PhotographStephanie Eihlpage 13
WindowsJim Harrispage 14
Little Pieces of YouStuart Albertpage 18
Slicing the AppleAmy Callpage 19
Winter WalkLarry Mitchellpage 19
Komical KellyJohn Fehrmannpage 20
Thermal SueJohn Fehrmannpage 20
Death PoemBob Zordanipage 21
Venice, ItalySherry L. Clinepage 22
RoadkillPhil Simpsonpage 24
I Hate CowsLori Delzer, Joe Crites, Becky Michaelpage 32
Telephone Operators: 1942Jim Harrispage 33
Expiration Date 3/8/65Edward Schellpage 34
Desert FloorPatrick Peterspage 35
PhotographLawrence McGownpage 36
PhotographStephanie Eihlpage 37
Coping with NightStuart Albertpage 38
PhotographDan Mountpage 38
One On OnePatrick Peterspage 39
An Acquired TasteTina Wrightpage 40
PhotographStephanie Eihlpage 40
PhotographStephanie Eihlpage 41
When Children Are Alone, The Devil SpeaksTom Greenpage 41
BobChristy Denphypage 42
Gut & ScissorsDane Buczkowskipage 42
This Old HouseAmy Callpage 43
MortgageTina Wrightpage 43https://thekeep.eiu.edu/vehicle/1048/thumbnail.jp
Hubble Space Telescope STIS Observations of GRB 000301C: CCD Imaging and Near-Ultraviolet MAMA Spectroscopy
We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the γ-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R ≃ 21.50 ± 0.15 source with no apparent host galaxy. An 8000 s, 1150 Å 18 on the line of sight to the OT. This measured redshift is conservatively a lower limit to the GRB redshift. However, as all other GRBs that have deep Hubble Space Telescope images appear to lie on the stellar field of a host galaxy, and as the large H I column density measured here and in later ground-based observations is unlikely on a random line of sight, we believe we are probably seeing absorption from H I in the host galaxy. In any case, this represents the largest direct redshift determination of a γ-ray burster to date. Our data are compatible with an OT spectrum represented by a power law with an intrinsic index α = 1.2 (f_ν ∝ ν^(-α)) and no extinction in the host galaxy, or with α = 0.5 and extinction by SMC-like dust in the OT rest frame with A_V = 0.15. The large N_(H I) and the lack of a detected host are similar to the situation for damped Lyα absorbers at z > 2
Supersymmetry without R-Parity and without Lepton Number
We investigate Supersymmetric models where neither R parity nor lepton number
is imposed. Neutrino masses can be kept highly suppressed compared to the
electroweak scale if the -terms in the superpotential are aligned with the
SUSY-breaking bilinear -terms. This situation arises naturally in the
framework of horizontal symmetries. The same symmetries suppress the trilinear
R parity violating terms in the superpotential to an acceptable level.Comment: 18 pages, harvma
- …