846 research outputs found
Photometry of SN 2002ic and Implications for the Progenitor Mass-Loss History
We present new pre-maximum and late-time optical photometry of the Type
Ia/IIn supernova 2002ic. These observations are combined with the published
V-band magnitudes of Hamuy et al. (2003) and the VLT spectrophotometry of Wang
et al. (2004) to construct the most extensive light curve to date of this
unusual supernova. The observed flux at late time is significantly higher
relative to the flux at maximum than that of any other observed Type Ia
supernova and continues to fade very slowly a year after explosion. Our
analysis of the light curve suggests that a non-Type Ia supernova component
becomes prominent days after explosion. Modeling of the non-Type Ia
supernova component as heating from the shock interaction of the supernova
ejecta with pre-existing circumstellar material suggests the presence of a
cm gap or trough between the progenitor system and the
surrounding circumstellar material. This gap could be due to significantly
lower mass-loss years prior to explosion or
evacuation of the circumstellar material by a low-density fast wind. The latter
is consistent with observed properties of proto-planetary nebulae and with
models of white-dwarf + asymptotic giant branch star progenitor systems with
the asymptotic giant branch star in the proto-planetary nebula phase.Comment: accepted for publication in Ap
SweetSpot: Near-Infrared Observations of Thirteen Type Ia Supernovae from a New NOAO Survey Probing the Nearby Smooth Hubble Flow
We present 13 Type Ia supernovae (SNe Ia) observed in the restframe
near-infrared (NIR) from 0.02 < z < 0.09 with the WIYN High-resolution Infrared
Camera (WHIRC) on the WIYN 3.5-m telescope. With only 1-3 points per light
curve and a prior on the time of maximum from the spectrum used to type the
object we measure an H-band dispersion of spectroscopically normal SNe Ia of
0.164 mag. These observations continue to demonstrate the improved standard
brightness of SNe Ia in H-band even with limited data. Our sample includes two
SNe Ia at z ~ 0.09, which represent the most distant restframe NIR H-band
observations published to date.
This modest sample of 13 NIR SNe Ia represent the pilot sample for
"SweetSpot" - a three-year NOAO Survey program that will observe 144 SNe Ia in
the smooth Hubble flow. By the end of the survey we will have measured the
relative distance to a redshift of z ~ 0.05 to 1%. Nearby Type Ia supernova (SN
Ia) observations such as these will test the standard nature of SNe Ia in the
restframe NIR, allow insight into the nature of dust, and provide a critical
anchor for future cosmological SN Ia surveys at higher redshift.Comment: 36 pages, 8 figures, Submitted to Ap
Novae as a Mechanism for Producing Cavities around the Progenitors of SN 2002ic and Other SNe Ia
We propose that a nova shell ejected from a recurrent nova progenitor system
created the evacuated region around the explosion center of SN 2002ic. In this
picture, periodic shell ejections due to nova explosions on a white dwarf sweep
up the slow wind from the binary companion, creating density variations and
instabilities that lead to structure in the circumstellar medium (CSM). Our
model naturally explains the observed gap between the supernova explosion
center and the CSM in SN 2002ic, accounts for the density variations observed
in the CSM, and resolves the coincidence problem of the timing of the explosion
of SN 2002ic with respect to the apparent cessation of mass-loss in the
progenitor system. We also consider such nova outburst sweeping as a generic
feature of Type Ia supernovae with recurrent nova progenitors.Comment: Accepted to ApJL. 11 pages, 1 tabl
The First Data Release from SweetSpot: 74 Supernovae in 36 Nights on WIYN+WHIRC
SweetSpot is a three-year National Optical Astronomy Observatory (NOAO)
Survey program to observe Type Ia supernovae (SNe Ia) in the smooth Hubble flow
with the WIYN High-resolution Infrared Camera (WHIRC) on the WIYN 3.5-m
telescope. We here present data from the first half of this survey, covering
the 2011B-2013B NOAO semesters, and consisting of 493 calibrated images of 74
SNe Ia observed in the rest-frame near-infrared (NIR) from .
Because many observed supernovae require host galaxy subtraction from templates
taken in later semesters, this release contains only the 186 NIR () data
points for the 33 SNe Ia that do not require host-galaxy subtraction. The
sample includes 4 objects with coverage beginning before the epoch of B-band
maximum and 27 beginning within 20 days of B-band maximum. We also provide
photometric calibration between the WIYN+WHIRC and Two-Micron All Sky Survey
(2MASS) systems along with light curves for 786 2MASS stars observed alongside
the SNe Ia. This work is the first in a planned series of three SweetSpot Data
Releases. Future releases will include the full set of images from all 3 years
of the survey, including host-galaxy reference images and updated data
processing and host-galaxy reference subtraction. SweetSpot will provide a
well-calibrated sample that will help improve our ability to standardize
distance measurements to SNe Ia, examine the intrinsic optical-NIR colors of
SNe Ia at different epochs, explore nature of dust in other galaxies, and act
as a stepping stone for more distant, potentially space-based surveys.Comment: Published in AJ. 10 tables. 11 figures. Lightcurve plots included as
a figureset and available in source tarball. Data online at
http://www.phyast.pitt.edu/~wmwv/SweetSpot/DR1_data
Dark Energy Accretion onto a Black Hole in an Expanding Universe
By using the solution describing a black hole embedded in the FLRW universe,
we obtain the evolving equation of the black hole mass expressed in terms of
the cosmological parameters. The evolving equation indicates that in the
phantom dark energy universe the black hole mass becomes zero before the Big
Rip is reached.Comment: 7 pages, no figures, errors is correcte
Interacting Cosmic Fluids in Brans-Dicke Cosmology
We provide a detailed description for power-law scaling FRW cosmological
models in Brans-Dicke theory dominated by two interacting fluid components
during the expansion of the universe.Comment: 13 pages, 8 figure
Precision measurements of large scale structure with future type Ia supernova surveys
Type Ia supernovae are currently the best known standard candles at
cosmological distances. In addition to providing a powerful probe of dark
energy they are an ideal source of information about the peculiar velocity
field of the local universe. Even with the very small number of supernovae
presently available it has been possible to measure the dipole and quadrupole
of the local velocity field out to z~0.025. With future continuous all-sky
surveys like the LSST project the luminosity distances of tens of thousands of
nearby supernovae will be measured accurately. This will allow for a
determination of the local velocity structure of the universe as a function of
redshift with unprecedented accuracy, provided the redshifts of the host
galaxies are known. Using catalogues of mock surveys we estimate that future
low redshift supernova surveys will be able to probe sigma-8 to a precision of
roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and
weak lensing surveys and with a relatively modest observational effort it will
provide a crucial cross-check on future measurements of the matter power
spectrum.Comment: 18 pages, 9 figures, submitted to JCA
Improving the LSST dithering pattern and cadence for dark energy studies
The Large Synoptic Survey Telescope (LSST) will explore the entire southern
sky over 10 years starting in 2022 with unprecedented depth and time sampling
in six filters, . Artificial power on the scale of the 3.5 deg LSST
field-of-view will contaminate measurements of baryonic acoustic oscillations
(BAO), which fall at the same angular scale at redshift . Using the
HEALPix framework, we demonstrate the impact of an "un-dithered" survey, in
which of each LSST field-of-view is overlapped by neighboring
observations, generating a honeycomb pattern of strongly varying survey depth
and significant artificial power on BAO angular scales. We find that adopting
large dithers (i.e., telescope pointing offsets) of amplitude close to the LSST
field-of-view radius reduces artificial structure in the galaxy distribution by
a factor of 10. We propose an observing strategy utilizing large dithers
within the main survey and minimal dithers for the LSST Deep Drilling Fields.
We show that applying various magnitude cutoffs can further increase survey
uniformity. We find that a magnitude cut of removes significant
spurious power from the angular power spectrum with a minimal reduction in the
total number of observed galaxies over the ten-year LSST run. We also determine
the effectiveness of the observing strategy for Type Ia SNe and predict that
the main survey will contribute 100,000 Type Ia SNe. We propose a
concentrated survey where LSST observes one-third of its main survey area each
year, increasing the number of main survey Type Ia SNe by a factor of
1.5, while still enabling the successful pursuit of other science
drivers.Comment: 9 pages, 6 figures, published in SPIE proceedings; corrected typo in
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