342 research outputs found
The Sizes of z ∼ 9-10 Galaxies Identified in the Brightest of Reionizing Galaxies (BoRG) Survey
Redshift z = 9-10 object selection is the effective limit of Hubble Space Telescope (HST) imaging capability, even when confirmed with Spitzer. If only a few photometry data points are available, it becomes attractive to add criteria based on their morphology in these J- and H-band images. One could do so through visual inspection, a size criterion, or alternate morphometrics. We explore a vetted sample of Brightest of Reionizing Galaxies (BoRG) z ∼ 9 and z ∼ 10 candidate galaxies and the object rejected by Morishita+ to explore the utility of a size criterion in z = 9-10 candidate selection. A stringent, point-spread function (PSF)-corrected effective radius criterion (re \u3c 0″.3) would result in the rejection of 65%-70% of the interlopers visually rejected by Morishita et al. It may also remove up to ∼20% of bona fide brightest (L ≫ L∗) z = 9 or 10 candidates from a BoRG selected sample based on the Mason et al. luminosity functions, assuming the Holwerda et al. z ∼ 9 size-luminosity relation. We argue that including a size constraint in lieu of a visual inspection may serve in wide-field searches for these objects in, e.g., Euclid or HST archival imaging with the understanding that some brightest (L ≫ L∗) candidates may be missed. The sizes of the candidates found by Morishita et al. follow the expected size distribution of z ∼ 9 for bright galaxies, consistent with the log normal in Shibuya et al. and single objects. Two candidates show high star formation surface density (ΣSFR \u3e 25M⊙ kpc-2) and all merit further investigation and follow-up observations
The Sizes of Galaxies Identified in the BoRG Survey
Redshift object selection is the effective limit of Hubble Space
Telescope imaging capability, even when confirmed with Spitzer. If only a few
photometry data points are available, it becomes attractive to add criteria
based on their morphology in these J- and H-band images.
One could do so through visual inspection, a size criterion, or alternate
morphometrics. We explore a vetted sample of BoRG and
candidate galaxies and the object rejected by Morishita+ (2018) to explore the
utility of a size criterion in z=9-10 candidate selection. A stringent,
PSF-corrected effective radius criterion (r_e<0\farcs3) would result in the
rejection of 65-70\% of the interlopers visually rejected by Morishita+. It may
also remove up to \% of bona-fide brightest () z=9 or 10
candidates from a BoRG selected sample based on the Mason+ (2015) luminosity
functions, assuming the Holwerda+ (2015) size-luminosity relation. We
argue that including a size constraint in lieu of a visual inspection may serve
in wide-field searches for these objects in e.g. EUCLID or HST archival imaging
with the understanding that some brightest () candidates may be missed.
The sizes of the candidates found by Morishita+ (2018) follow the expected
size distribution of for bright galaxies, consistent with the
lognormal in Shibuya+ (2015) and single objects. Two candidates show high
star-formation surface density () and all
merit further investigation and follow-up observations.Comment: 9 Figures, 1 table, 13 pages, accepted for publication in The
Astronomical Journa
Quasiparticle Properties in Effective Field Theory
The quasiparticle concept is an important tool for the description of
many-body systems. We study the quasiparticle properties for dilute Fermi
systems with short-ranged, repulsive interactions using effective field theory.
We calculate the proper self-energy contributions at order (K_f/Lambda)^3,
where Lambda is the short-distance scale that sets the size of the effective
range parameters and K_f the Fermi momentum. The quasiparticle energy, width,
and effective mass to order O(K_f/Lambda)^3 are derived from the calculated
self-energy.Comment: 15 pages, revtex4, 4 PS figure
Substellar and low-mass dwarf identification with near-infrared imaging space observatories
Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and WFIRST) combinations. Results. The Euclid filters perform equally well as HST wide filters in discriminating between broad types of brown dwarfs. WFIRST performs similarly well, despite a wider selection of filters. However, subtyping with any combination of Euclid and WFIRST observations remains uncertain due to the lack of medium, or narrow-band filters. We argue that a medium band added to the WFIRST filter selection would greatly improve its ability to preselect brown dwarfs its imaging surveys. Conclusions. The HST filters used in high-redshift searches are close to optimal to identify broad stellar type. However, the addition of F127M to the commonly used broad filter sets would allow for unambiguous subtyping. An improvement over HST is one of two broad and medium filter combinations on JWST: pairing F140M with either F150W or F162M discriminates very well between subtypes
The Super Eight Galaxies: Properties of a Sample of Very Bright Galaxies at 7 \u3c z \u3c 8
We present the Super Eight galaxies - a set of very luminous, high-redshift (7.1 \u3c z \u3c 8.0) galaxy candidates found in the Brightest of Reionizing Galaxies (BoRG) Survey fields. The original sample includes eight galaxies that are Y-band dropout objects with H-band magnitudes of m H \u3c 25.5. Four of these objects were originally reported in Calvi et al. Combining new Hubble Space Telescope (HST) WFC3/F814W imaging and Spitzer IRAC data with archival imaging from BoRG and other surveys, we explore the properties of these galaxies. Photometric redshift fitting places six of these galaxies in the redshift range of 7.1 \u3c z \u3c 8.0, resulting in three new high-redshift galaxies and confirming three of the four high-redshift galaxy candidates from Calvi et al. We calculate the half-light radii of the Super Eight galaxies using the HST F160W filter and find that the Super Eight sizes are in line with the typical evolution of size with redshift. The Super Eights have a mean mass of log (M ∗/M o) ∼10, which is typical for sources in this luminosity range. Finally, we place our sample on the UV z ∼ 8 luminosity function and find that the Super Eight number density is consistent with other surveys in this magnitude and redshift range
The Polarizability of the Deuteron
The scalar and tensor polarizabilities of the deuteron are calculated using
the recently developed effective field theory that describes nucleon-nucleon
interactions. Leading and next-to-leading order contributions in the
perturbative expansion predict a scalar electric polarizability of 0.595 fm^3.
The tensor electric polarizability receives contributions starting at
next-to-leading order from the exchange of a single potential pion and is found
to be -0.062 fm^3. We compute the leading contributions to the scalar and
tensor magnetic polarizabilities, finding 0.067 fm^3 and 0.195 fm^3,
respectively.Comment: 13 pages, 4 figures as 6 eps files, latex. References adde
Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar
We study the process with
initial-state-radiation events produced at the PEP-II asymmetric-energy
collider. The data were recorded with the BaBar detector at center-of-mass
energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454
. We investigate the mass
distribution in the region from 3.5 to 5.5 . Below 3.7
the signal dominates, and above 4
there is a significant peak due to the Y(4260). A fit to
the data in the range 3.74 -- 5.50 yields a mass value
(stat) (syst) and a width value (stat)(syst) for this state. We do not
confirm the report from the Belle collaboration of a broad structure at 4.01
. In addition, we investigate the system
which results from Y(4260) decay
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
- …