This paper describes new deep 3.6 and 4.5 m imaging of three UltraVISTA near-infrared survey stripes within the COSMOS field. The observations were carried out with Spitzer's Infrared Array Camera ...(IRAC) for the Spitzer Matching Survey of the UltraVISTA Deep Stripes (SMUVS). In this work we present our data reduction techniques, and document the resulting mosaics, coverage maps, and catalogs in both IRAC passbands for the three easternmost UltraVISTA survey stripes, covering a combined area of about 0.66 deg2, of which 0.45 deg2 have at least 20 hr of integration time. SMUVS reaches point-source sensitivities of about 25.0 AB mag (0.13 Jy) at both 3.6 and 4.5 m, with a significance of 4 , accounting for both survey sensitivity and source confusion. To this limit the SMUVS catalogs contain a total of ∼350,000 sources, each of which is detected significantly in at least one IRAC band. Because of its uniform and high sensitivity, relatively large area coverage, and the wide array of ancillary data available in COSMOS, the SMUVS survey will be useful for a large number of cosmological investigations. We make all images and catalogs described herein publicly available via the Spitzer Science Center.
HIAF (High Intensity heavy ion Accelerator Facility), a new facility planned in China for heavy ion related researches, consists of two ion sources, a high intensity Heavy Ion Superconducting Linac ...(HISCL), a 45 Tm Accumulation and Booster Ring (ABR-45) and a multifunction storage ring system. The key features of HIAF are unprecedented high pulse beam intensity and versatile operation mode. The HIAF project aims to expand nuclear and related researches into presently unreachable region and give scientists possibilities to conduct cutting-edge researches in these fields. The general description of the facility is given in this article with a focus on the accelerator design.
Powerful terahertz (THz) radiation is observed from large-scale underdense preplasmas in front of a solid target irradiated obliquely with picosecond relativistic intense laser pulses. The radiation ...covers an extremely broad spectrum with about 70% of its energy located in the high frequency regime over 10 THz. The pulse energy of the radiation is found to be above 100 μJ per steradian in the laser specular direction at an optimal preplasma scale length around 40-50 μm. Particle-in-cell simulations indicate that the radiation is mainly produced by linear mode conversion from electron plasma waves, which are excited successively via stimulated Raman scattering instability and self-modulated laser wakefields during the laser propagation in the preplasma. This radiation can be used not only as a powerful source for applications, but also as a unique diagnostic of parametric instabilities of laser propagation in plasmas.
We present high-resolution submillimeter interferometric imaging of two of the brightest high-redshift submillimeter galaxies known: GN 20 and AzTEC1 at 0.8 super(image )and 0.3 super(image ) ...resolution, respectively. Our data-the highest resolution submillimeter imaging of high-redshift sources accomplished to date-were collected in three different array configurations: compact, extended, and very extended. We derive angular sizes of 0.6 super(image ) and 1.0 super(image ) for GN 20 and 0.3 super(image ) and 0.4 super(image ) for AzTEC1 from modeling their visibility functions as a Gaussian and an elliptical disk, respectively. Because both sources are B-band dropouts, they likely lie within a relatively narrow redshift window around image, which indicates their angular extent corresponds to physical scales of 4-8 and 1.5-3 kpc, respectively, for the starburst region. By way of a series of simple assumptions, we find preliminary evidence that these hyperluminous starbursts-with star formation rates >1000 image yrimage -are radiating at or close to their Eddington limit. Should future high-resolution observations indicate that these two objects are typical of a population of high-redshift Eddington-limited starbursts, this could have important consequences for models of star formation and feedback in extreme environments.
We report on the identification of the old stellar population galaxy candidates at z ≳ 5. We developed a new infrared color selection scheme to isolate galaxies with the strong Balmer breaks at z ≳ ...5, and applied it to the ultra-deep and wide infrared survey data from the Spitzer Extended Deep Survey (SEDS) and the UKIRT Infrared Deep Sky Survey. The eight objects satisfying K − 3.6 > 1.3 and K − 3.6 > 2.4(3.6 − 4.5) + 0.6 are selected in the 0.34 deg2 SEDS Ultra Deep Survey field. Rich multi-wavelength imaging data from optical to far-infrared are also used to reject blending sources and strong nebular line emitters, and we finally obtained the three most likely evolved galaxies at z ≳ 5. Their stacked spectral energy distribution is fitted well with the old stellar population template with M* = (7.5 ± 1.5) × 1010 M⊙, star formation rate = 0.9 ± 0.2 M⊙ yr−1, dust AV < 1, and age =0.7 ± 0.4 Gyr at z = 5.7 ± 0.6, where the dusty star-forming galaxies at z ∼ 2.8 are disfavored because of the faintness in the 24 μm. The stellar mass density of these evolved galaxy candidates, (6 ± 4) × 104 M⊙ Mpc−3, is much lower than that of star-forming galaxies, but the non-zero fraction suggests that initial star-formation and quenching have been completed by z ∼ 6.
Electron-ion recombination of Be-like 40Ar14+ has been measured by employing the electron-ion merged-beams method at the cooler storage ring CSRm. The measured absolute recombination rate ...coefficients for collision energies from 0 to 60 eV are presented, covering all dielectronic recombination (DR) resonances associated with 2s2 → 2s2p core transitions. In addition, strong trielectronic recombination (TR) resonances associated with 2s2 → 2p2 core transitions were observed. Both DR and TR processes lead to series of peaks in the measured recombination spectrum, which have been identified by the Rydberg formula. Theoretical calculations of recombination rate coefficients were performed using the state-of-the-art multi-configuration Breit-Pauli atomic structure code AUTOSTRUCTURE to compare with the experimental results. The plasma rate coefficients for DR+TR of Ar14+ were deduced from the measured electron-ion recombination rate coefficients in the temperature range from 103 to 107 K, and compared with calculated data from the literature. The experimentally derived plasma rate coefficients are 60% larger and 30% lower than the previously recommended atomic data for the temperature ranges of photoionized plasmas and collisionally ionized plasmas, respectively. However, good agreement was found between experimental results and the calculations by Gu and Colgan et al. The plasma rate coefficients deduced from experiment and calculated by the current AUTOSTRUCTURE code show agreement that is better than 30% from 104 to 107 K. The present results constitute a set of benchmark data for use in astrophysical modeling.
Metamorphic dehydration and partial melting are two important processes during continental collision. They have significant bearing on element transport at the slab interface under subduction‐zone ...P–T conditions. Petrological and geochemical insights into the two processes are provided by a comprehensive study of leucocratic veins in ultrahigh‐pressure (UHP) metamorphic rocks. This is exemplified by this study of a polymineralic vein within phengite‐bearing UHP eclogite in the Dabie orogen. The vein is primarily composed of quartz, kyanite, epidote and phengite, with minor accessory minerals such as garnet, rutile and zircon. Primary multiphase solid inclusions occur in garnet and epidote from the both vein and host eclogite. They are composed of quartz ± K‐feldspar ± plagioclase ± K‐bearing glass and exhibit irregular to negative crystal shapes that are surrounded by weak radial cracks. This suggests their precipitation from solute‐rich metamorphic fluid/melt that involved the reaction of phengite breakdown. Zircon U–Pb dating for the vein gave two groups of concordant ages at 217 ± 2 and 210 ± 2 Ma, indicating two episodes of zircon growth in the Late Triassic. The same minerals from the two rocks give consistent δ18O and δD values, suggesting that the vein‐forming fluid was directly derived from the host UHP eclogite. The vein is much richer in phengite and epidote than the host eclogite, suggesting that the fluid is associated with remarkable concentration of such water‐soluble elements as LILE and LREE migration. Garnet and rutile in the vein exhibit much higher contents of HREE (2.2–5.7 times) and Nb–Ta (1.8–2.0 times) than those in the eclogite, indicating that these normally water‐insoluble elements became mobile and then were sunken in the vein minerals. Thus, the vein‐forming agent would be primarily composed of the UHP aqueous fluid with minor amounts of the hydrous melt, which may even become a supercritical fluid to have a capacity to transport not only LILE and LREE but also HREE and HFSE at subduction‐zone metamorphic conditions. Taken together, significant amounts of trace elements were transported by the vein‐forming fluid due to the phengite breakdown inside the UHP eclogite during exhumation of the deeply subducted continental crust.
We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size ~2 arcsec) imaging of ...eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology-including the nature of SMGs with multiple radio counterparts and constraints on the physical scale of the far infrared-of the sample, and (3) find additional evidence for a population of extremely luminous, radio-dim SMGs that peaks at higher redshift than previous, radio-selected samples. In particular, the presence of such a population of high-redshift sources has important consequences for models of galaxy formation-which struggle to account for such objects even under liberal assumptions-and dust production models given the limited time since the big bang.
Abstract
We present redshifts for 2753 low-redshift galaxies between 0.03 ≲
z
spec
≲ 0.5 with 18 ≤
r
≤ 22 obtained with Hectospec at the Multi-Mirror Telescope. The observations targeted the XMM-LSS, ...ELAIS-N1 and DEEP2-3 fields, each of which covers ∼1 deg
2
. These fields are also part of the recently completed Canada–France–Hawaii Telescope Large Area
U
-band Deep Survey and ongoing Hyper Suprime-Cam deep fields surveys. The efficiency of our technique for selecting low-redshift galaxies is confirmed by the redshift distribution of our sources. In addition to redshifts, these high signal-to-noise ratio spectra are used to measure ages, metallicities, and nuclear activity levels. In combination with the photometric catalog in
u
,
g
,
r
,
i
,
z
,
y
down to 27 AB mag, we are able to study the galaxy population down to stellar masses of ∼10
8
M
⊙
. This paper presents the observational strategy, the reduction procedure and properties of the galaxy sample. (The catalog can be accessed through the survey’s website at
http://mips.as.arizona.edu/~cnaw/Faint_Low_z/
.)
Abstract
In order to study the surface interaction between binder and TKX-50, fluororubber F2603, ETPE, and BR were adhered to the surface of TKX-50 by the direct solvent volatilization method. The ...spreading coefficient and adhesion work between the three adhesives and TKX-50 were analyzed by a surficial performance test. The coating effect and safety of TKX-50 coated by three binders were discussed by XPS, SEM, and mechanical sensitivity. The results showed that F2603, ETPE, and BR were adhered to the surface of TKX-50 to form efficient spreading and bonding. The coating effect of F2603 on the TKX-50 was better than that of ETPE and BR, which improved the mechanical sensitivity of TKX-50. The results show that some binders could have positive effects on improving the safety of TKX-50.
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