27,966 research outputs found
Entangled Coherent State Qubits in an Ion Trap
We show how entangled qubits can be encoded as entangled coherent states of
two-dimensional centre-of-mass vibrational motion for two ions in an ion trap.
The entangled qubit state is equivalent to the canonical Bell state, and we
introduce a proposal for entanglement transfer from the two vibrational modes
to the electronic states of the two ions in order for the Bell state to be
detected by resonance fluorescence shelving methods.Comment: 4 pages, No figures, accepted to PRA, minor chang
An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample
We present high-resolution (30"-1') 12, 25, 60, and 100 micron images of 106
interacting galaxy systems contained in the IRAS Revised Bright Galaxy Sample
(RBGS, Sanders et al. 2003), a complete sample of all galaxies having a 60
micron flux density greater than 5.24 Jy. These systems were selected to have
at least two distinguishable galaxies separated by less than three average
galactic diameters, and thus we have excluded very widely separated systems and
very advanced mergers. The new complete survey has the same properties as the
prototype survey of Surace et al. 1993. We find no increased tendency for
infrared-bright galaxies to be associated with other infrared bright galaxies
among the widely separated pairs studied here. We find small enhancements in
far-infrared activity in multiple galaxy systems relative to RBGS
non-interacting galaxies with the same blue luminosity distribution. We also
find no differences in infrared activity (as measured by infrared color and
luminosity) between late and early-type spiral galaxies.Comment: 49 pages, 13 figures. To appear in the Astronomical Journal. Figures
have been degraded due to space considerations. A PDF version with higher
quality figures is available at
http://humu.ipac.caltech.edu/~jason/pubs/surace_hires.pd
The Role of Starburst-AGN composites in Luminous Infrared Galaxy Mergers: Insights from the New Optical Classification Scheme
We investigate the fraction of starbursts, starburst-AGN composites,
Seyferts, and LINERs as a function of infrared luminosity (L_IR) and merger
progress for ~500 infrared-selected galaxies. Using the new optical
classifications afforded by the extremely large data set of the Sloan Digital
Sky Survey, we find that the fraction of LINERs in IR-selected samples is rare
(< 5%) compared with other spectral types. The lack of strong infrared emission
in LINERs is consistent with recent optical studies suggesting that LINERs
contain AGN with lower accretion rates than in Seyfert galaxies. Most
previously classified infrared-luminous LINERs are classified as starburst-AGN
composite galaxies in the new scheme. Starburst-AGN composites appear to
"bridge" the spectral evolution from starburst to AGN in ULIRGs. The relative
strength of the AGN versus starburst activity shows a significant increase at
high infrared luminosity. In ULIRGs (L_IR >10^12 L_odot), starburst-AGN
composite galaxies dominate at early--intermediate stages of the merger, and
AGN galaxies dominate during the final merger stages. Our results are
consistent with models for IR-luminous galaxies where mergers of gas-rich
spirals fuel both starburst and AGN, and where the AGN becomes increasingly
dominant during the final merger stages of the most luminous infrared objects.Comment: 30 pages, 19 figures, 10 tables, ApJ accepte
Major Galaxy Mergers and the Growth of Supermassive Black Holes in Quasars
Despite observed strong correlations between central supermassive black holes
(SMBHs) and star-formation in galactic nuclei, uncertainties exist in our
understanding of their coupling. We present observations of the ratio of
heavily-obscured to unobscured quasars as a function of cosmic epoch up to z~3,
and show that a simple physical model describing mergers of massive, gas-rich
galaxies matches these observations. In the context of this model, every
obscured and unobscured quasar represent two distinct phases that result from a
massive galaxy merger event. Much of the mass growth of the SMBH occurs during
the heavily-obscured phase. These observations provide additional evidence for
a causal link between gas-rich galaxy mergers, accretion onto the nuclear SMBH
and coeval star formation.Comment: Accepted for publication in Science. Published by Science Express on
March 25th. 17 pages, 5 figures, including supplemental online materia
Recommended from our members
Clinical impact of splicing in neurodevelopmental disorders.
Clinical exome sequencing is frequently used to identify gene-disrupting variants in individuals with neurodevelopmental disorders. While splice-disrupting variants are known to contribute to these disorders, clinical interpretation of cryptic splice variants outside of the canonical splice site has been challenging. Here, we discuss papers that improve such detection
- …