bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Identification of 10 kpc [C ii] 158 μm Halos around Star-forming Galaxies at z = 5–7
Authors: Fujimoto Seiji , Ouchi Masami , Ferrara Andrea , Pallottini Andrea , Ivison R. J. , Behrens Christoph , Gallerani Simona , Arata Shohei , Yajima Hidenobu , Nagamine Kentaro 
Published: December 2019

Abstract
We report the discovery of 10 kpc [C ii] 158 μm halos surrounding star-forming galaxies in the early universe. We choose deep Atacama Large Millimeter/submillimeter Array data for 18 galaxies, each with a star formation rate of ≃10–70 M
⊙ with no signature of an active galactic nucleus whose [C ii] lines are individually detected at z = 5.153–7.142, and we conduct stacking of the [C ii] lines and dust continuum in the uv-visibility plane. The radial profiles of the surface brightnesses show a 10 kpc scale [C ii] halo at the 9.2σ level, significantly more extended than the Hubble Space Telescope stellar continuum data by a factor of ∼5 on the exponential-profile basis, as well as the dust continuum. We compare the radial profiles of [C ii] and Lyα halos universally found in star-forming galaxies at this epoch, and we find that the scale lengths agree within the 1σ level. While two independent hydrodynamic zoom-in simulations match the dust and stellar continuum properties, the simulations cannot reproduce the extended [C ii] line emission. The existence of the extended [C ii] halo is evidence of outflow remnants in the early galaxies and suggests that the outflows may be dominated by cold-mode outflows expelling the neutral gas.
A Remarkably Narrow RHESSI X-Ray Flare on 2011 September 25
Authors: Dennis Brian. R. , Tolbert Anne K. 
Published: December 2019

Abstract
The unusually narrow X-ray source imaged with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) during an impulsive spike lasting for ∼10 s during the Geostationary Operational Environmental Satellite C7.9 flare on 2011 September 25 (SOL2011-09-25T03:32) was only ∼2″ wide and ∼10″ long. Comparison with Helioseismsic and Magnetic Imager magnetograms and Atmospheric Imaging Assembly images at 1700 Å shows that the X-ray emission was primarily from a long ribbon in the region of positive polarity with little if any emission from the negative polarity ribbon. However, a thermal plasma source density of ∼1012 cm−3 estimated from the RHESSI-derived emission measure and source area showed that this could best be interpreted as a coronal hard X-ray source in which the accelerated electrons with energies less than ∼50 keV were stopped by Coulomb collisions in the corona, thus explaining the lack of the more usual bright X-ray footpoints. Analysis of RHESSI spectra shows greater consistency with a multi-temperature distribution and a low-energy cutoff to the accelerated electron spectrum of 22 keV compared to 12 keV if a single-temperature distribution is assumed. This leads to a change in the lower limit on the total energy in electrons by an order of magnitude, given the steepness of the best-fit electron spectrum with a power-law index of ∼6.
Morphological Classification of G-band Bright Points Based on Deep Learning
Authors: Yang Yunfei , Li Xiaojie , Bai Xianyong , Zhou Huituan , Liang Bo , Zhang Xiaoli , Feng Song 
Published: December 2019

Abstract
The G-band bright points (GBPs) are driven by the granular convection flow, and appear with different morphologies in the quiet Sun, such as points, elongated chains, and knees. A point-like GBP represents a single slender flux tube, while the others represent the interaction of several slender flux tubes. This paper presents a deep-learning method, GBPs Mask Region-based Convolutional Neural Networks (GBP-MRCNN) for morphological classification of GBPs. A training set including 10,404 samples and a validation set including 2057 samples have been built. A total of 906 images as a testing set have been detected, segmented, and classified. They consist of 74,973 points (88.3%), 8660 elongated chains (10.2%), and 1239 knees (1.5%). GBP-MRCNN has achieved an efficient classification of GBPs with a mean average precision of 0.93. For points, elongated chains, and knees, the quiet Sun fractional area average values are 0.47%, 0.14%, and 0.03%, respectively. Correspondingly, the mean areas are (2.02 ± 0.69) × 104, (6.17 ± 1.71) × 104 and (6.99 ± 1.74) × 104 km2, respectively. The maximum intensity contrasts are 1.05 ± 0.12, 1.18 ± 0.17, and 1.36 ± 0.17, respectively. The mean eccentricities of points and elongated chains are 0.48 ± 0.23 and 0.89 ± 0.01, respectively. We adopt constituent points to describe how many points constitute a nonpoint-like GBP. The mean constituent points of elongated chains and knees are estimated as 2.77 ± 0.57 and 3.06 ± 0.65, respectively. The maximum length of the elongated chains can extend to over 1000 km, which corresponds to over eight single slender flux tubes. The characteristics of GBPs with different morphologies can be explained by the interaction between magnetic flux tubes and photospheric convection, and then help to build improved magnetic flux tube models.
Cosmological Constraints from the Redshift Dependence of the Alcock–Paczynski Effect: Fourier Space Analysis
Authors: Luo Xiaolin , Wu Ziyong , Li Miao , Li Zhigang , Sabiu Cristiano G. , Li Xiao-Dong 
Published: December 2019

Abstract
The tomographic Alcock–Paczynski (AP) method utilizes the redshift evolution of the AP distortion to place constraints on cosmological parameters. In previous works, it was performed via the anisotropic two-point correlation function statistic. In this work we consider the feasibility of conducting the analysis in the Fourier domain. We use the integrated galaxy power spectrum as a function of direction,

, to quantify the magnitude of anisotropy in the large-scale structure clustering, and use its redshift variation to do the AP test. The method is tested on the large, high-resolution Big-MultiDark Planck simulation at redshifts z = 0–1. Testing the redshift evolution of

in the true cosmology and cosmologies deviating from the truth with δΩ
m
= 0.1, δw = 0.3, we find that the redshift evolution of the AP distortion overwhelms the redshift space distortions effects by a factor of ∼1.7–3.6. The method works well throughout the range of k ∈ (0.2, 1.8) h Mpc−1. We tune the halo mass within the range 2 × 1013–1014
M
⊙, and find that the change of halo bias results in ≲5% change in

, which is less significant compared with the cosmological effect. Our work shows that it is feasible to conduct the tomographic AP analysis in the Fourier space.
Narrow-absorption Line Complex. IV. Line-driven Radiative Outflows in Broad-absorption Line Quasars
Authors: Lu 陆 Wei-Jian 伟坚 , Lin 林 Ying-Ru 樱如 
Published: December 2019

Abstract
It has been reported that some broad-absorption lines (BALs) in quasar spectra can be decomposed into multiple narrow-absorption lines (NALs), which we define as “Type N BALs.” In this paper, using the spectra of 2005 BAL quasars from the Sloan Digital Sky Survey (SDSS), we have visually identified a total of 6764 C iv
λλ1548 and 1551 NAL systems with 1.4186 ≤ z
abs ≤ 3.8005, including 4174 C iv NAL systems within BAL troughs from 1349 quasars and 2590 outside BAL troughs from 1319 quasars. About two-thirds of the BAL quasars in the total sample contain Type N BALs, indicating the ubiquity of Type N BALs, which serve as a new perspective for studying outflows in the context of the NAL complex. Moreover, we find that, for both samples of C iv NAL systems within and outside BAL troughs, the distributions of velocity separation among distinct C iv NAL systems in the same quasar show significant excesses at the positions of C iv and Si iv doublet splittings, which offers statistical evidence for the idea that radiative forces play a significant role in driving both BAL and NAL outflows in BAL quasars.
Observational Analysis on the Early Evolution of a CME Flux Rope: Preflare Reconnection and Flux Rope’s Footpoint Drift
Authors: Chen Hechao , Yang Jiayan , Ji Kaifan , Duan Yadan 
Published: December 2019

Abstract
We study the early evolution of a hot-channel-like magnetic flux rope (MFR) toward eruption. Combining with imaging observation and magnetic field extrapolation, we find that the hot channel possibly originated from a preexisting seed MFR with a hyperbolic flux tube (HFT). In the precursor phase, three-dimensional tether-cutting reconnection at the HFT is most likely resulting in the heating and buildup of the hot channel. In this process, the forming hot channel was rapidly enlarged at its spatial size and slipped its feet to two remote positions. Afterward, it instantly erupted outwards with an exponential acceleration, leaving two core dimmings near its feet. We suggest that preflare reconnection at the HFT played a crucial role in enlarging the seed MFR and facilitating the onset of its final solar eruption. Moreover, a recently predicted drifting of MFR’s footpoints was detected at both core dimmings. In particular, we find that MFR’s west footpoint drift was induced by a new reconnection geometry among the erupting MFR’s leg and thereby inclined arcades. As MFR’s west footpoints gradually drifted to a new position, a set of newborn atypical flare loops connected into the west core dimming, causing a rapid decrease of dimmed area inside this core dimming and also generating a secondary flare ribbon at their remote feet. This reveals that core dimmings may suffer a pronounced diminishment due to the eruptive MFR’s footpoint drift, implying that mapping the real footpoints of the erupting MFR down to the Sun’s surface is more difficult than previously thought.
Compressible and Incompressible Magnetic Turbulence Observed in the Very Local Interstellar Medium by Voyager 1
Authors: Zank G. P. , Nakanotani M. , Webb G. M. 
Published: December 2019

Abstract

Voyager 1 observed Kolmogorov-like (k
−5/3) compressible turbulence just upwind of the heliopause. Subsequent measurements by Voyager 1 further from the heliopause revealed that the observed fluctuations were now fully incompressible, with a k
−5/3 spectrum that was essentially identical to that of the earlier compressible spectrum. Zank et al. showed that only compressible fast magnetosonic modes could be transmitted from the inner heliosheath into the very local interstellar medium (VLISM), and could exhibit a k
−5/3 spectrum. We show here that the small plasma beta VLISM admits three-wave interactions between a fast magnetosonic mode, a zero-frequency mode, and an Alfvén wave. The fast magnetosonic mode is converted to an incompressible Alfvén (or zero-frequency) mode with wavenumber almost identical to that of the initial compressible fast mode. The initial compressible and generated incompressible spectra are essentially identical. For the wavelength range observed by Voyager 1, we estimate that compressible fast modes are fully mode-converted to incompressible fluctuations within ∼10 au of the heliopause. We suggest that the VLISM magnetic field spectrum is a superposition of a higher amplitude ∼k
−5/3 spectrum of heliospheric origin with an estimated correlation length ∼30 au, having a minimum wavenumber ∼(100)−1 (au)−1, and a lower amplitude (possibly local) ISM k
−5/3 spectrum, the latter possessing an outer scale ≥2 pc. We suggest that the transmission of compressible turbulence from an inner asterosheath into the local circumstellar interstellar medium surrounding a star, and the subsequent mode conversion to incompressible turbulence, may be a general mechanism by which stars drive turbulence in the interstellar medium.
Spectroscopy of the Young Stellar Association Price-Whelan 1: Origin in the Magellanic Leading Arm and Constraints on the Milky Way Hot Halo
Authors: Nidever David L. , Price-Whelan Adrian M. , Choi Yumi , Beaton Rachael L. , Hansen Terese T. , Boubert Douglas , Aguado David , Ezzeddine Rana , Oh Semyeong , Evans N. Wyn 
Published: December 2019

Abstract
We report spectroscopic measurements of stars in the recently discovered young stellar association Price-Whelan 1 (PW 1), which was found in the vicinity of the Leading Arm (LA) of the Magellanic Stream (MS). We obtained Magellan+MIKE high-resolution spectra of the 28 brightest stars in PW 1 and used The Cannon to determine their stellar parameters. We find that the mean metallicity of PW 1 is [Fe/H] = −1.23 with a small scatter of 0.06 dex and the mean RV is

= 276.7

with a dispersion of

. Our results are consistent in

,

, and [Fe/H] with the young and metal-poor characteristics (116 Myr and [Fe/H] = −1.1) determined for PW 1 from our discovery paper. We find a strong correlation between the spatial pattern of the PW 1 stars and the LA II gas with an offset of −10.°15 in

and +1.°55 in

. The similarity in metallicity, velocity, and spatial patterns indicates that PW 1 likely originated in LA II. We find that the spatial and kinematic separation between LA II and PW 1 can be explained by ram pressure from Milky Way (MW) gas. Using orbit integrations that account for the LMC and MW halo and outer disk gas, we constrain the halo gas density at the orbital pericenter of PW 1 to be

and the disk gas density at the midplane at

to be

. We, therefore, conclude that PW 1 formed from the LA II of the MS, making it a powerful constraint on the MW–Magellanic interaction.
Influence of Density Dependence of Symmetry Energy in Hot and Dense Matter for Supernova Simulations
Authors: Sumiyoshi Kohsuke , Nakazato Ken’ichiro , Suzuki Hideyuki , Hu Jinniu , Shen Hong 
Published: December 2019

Abstract
We study the influence of density-dependent symmetry energy at high densities in simulations of core-collapse supernovae, black hole formation, and proto–neutron star cooling by extending the relativistic mean field (RMF) theory used for the Shen equation-of-state (EOS) table. We adopt the extended RMF theory to examine the density dependence of the symmetry energy with a small value of the slope parameter L, while the original properties of the symmetric nuclear matter are unchanged. In order to assess matter effects at high densities, we perform numerical simulations of gravitational collapse of massive stars adopting the EOS table at high densities beyond 1014 g cm−3 with the small L value, which is in accord with the experimental and observational constraints, and compare them with the results obtained by using the Shen EOS. Numerical results for 11.2 and 15 M
⊙ stars exhibit minor effects around the core bounce and in the following evolution for 200 ms. Numerical results for 40 and 50 M
⊙ stars reveal a shorter duration toward the black hole formation with a smaller maximum mass for the small-L case. Numerical simulations of proto–neutron star cooling over 10 s through neutrino emissions demonstrate increasing effects of the symmetry energy at high densities. Neutrino cooling drastically proceeds in a relatively long timescale with high luminosities and average energies with the small symmetry energy. Evolution toward the cold neutron star is affected because of the different behavior of neutron-rich matter, while supernova dynamics around core bounce remains similar in less neutron-rich environments.
Modulation of Galactic Cosmic Rays from Helium to Nickel in the Inner Heliosphere
Authors: Shen Z.-N. , Qin G. , Zuo Pingbing , Wei Fengsi 
Published: December 2019

Abstract
Galactic cosmic-ray (GCR) helium and heavier ions are important sources of space radiation, and their elemental spectra and composition can help us better understand the transport in both the galaxy and the heliosphere. A model based on the numerical solution of Parker’s transport equation is used to study the modulation of GCR helium and heavier ions in the inner heliosphere. The model incorporates a modified Parker heliospheric magnetic field, time-dependent diffusion and drift model, time-delayed heliosphere, and randomly determined solar magnetic polarity during solar maximum. We set the outer boundary of modulation at 85 au, and the reference unmodulated GCR energy spectra for GCR helium and heavier ions, which are assumed to have a general form, are determined by fitting the numerical results to the selected GCR measurements, e.g., BESS, ACE/CRIS, HEAO-3-C2, etc. In addition, we use the Sun’s polar magnetic field data from NSO/NISP to determine the possibility of A > 0 during the recent solar maximum, and it gives an improved numerical result during the period 2013–2015. Finally, the fitted unmodulated GCR energy spectra are used to study the long-term modulation of GCRs of helium and heavier ions, and the computed results show good agreement with various GCR measurements.
Evaluating the Classification of Fermi BCUs from the 4FGL Catalog Using Machine Learning
Authors: Kang 康 Shi-Ju 世举 , Li Enze , Ou Wujing , Zhu Kerui , Fan Jun-Hui , Wu Qingwen , Yin Yue 
Published: December 2019

Abstract
The recently published fourth Fermi Large Area Telescope source catalog (4FGL) reports 5065 gamma-ray sources in terms of direct observational gamma-ray properties. Among the sources, the largest population is the active galactic nuclei (AGNs), which consists of 3137 blazars, 42 radio galaxies, and 28 other AGNs. The blazar sample comprises 694 flat-spectrum radio quasars (FSRQs), 1131 BL Lac- type objects (BL Lacs), and 1312 blazar candidates of an unknown type (BCUs). The classification of blazars is difficult using optical spectroscopy given the limited knowledge with respect to their intrinsic properties, and the limited availability of astronomical observations. To overcome these challenges, machine-learning algorithms are being investigated as alternative approaches. Using the 4FGL catalog, a sample of 3137 Fermi blazars with 23 parameters is systematically selected. Three established supervised machine-learning algorithms (random forests (RFs), support vector machines (SVMs), artificial neural networks (ANNs)) are employed to general predictive models to classify the BCUs. We analyze the results for all of the different combinations of parameters. Interestingly, a previously reported trend the use of more parameters leading to higher accuracy is not found. Considering the least number of parameters used, combinations of eight, 12 or 10 parameters in the SVM, ANN, or RF generated models achieve the highest accuracy (Accuracy ≃91.8%, or ≃92.9%). Using the combined classification results from the optimal combinations of parameters, 724 BL Lac type candidates and 332 FSRQ type candidates are predicted; however, 256 remain without a clear prediction.
Active Galactic Nuclei with Ultrafast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind
Authors: Lu Kai-Xing , Bai Jin-Ming , Zhang Zhi-Xiang , Du Pu , Hu Chen , Kim Minjin , Wang Jian-Min , Ho Luis C. , Li Yan-Rong , Bian Wei-Hao , Yuan Ye-Fei , Xiao Ming , Feng Hai-Cheng , Wang Jian-Guo , Xu Liang , Ding Xu , Yu Xiao-Guang , Xin Yu-Xin , Ye Kai , Wang Chuan-Jun , Lun Bao-Li , Zhang Ju-Jia , Zhang Xi-Liang , Ji Kai-Fan , Fan Yu-Feng , Chang Liang 
Published: December 2019

Abstract
We developed a spectroscopic monitoring project to investigate the kinematics of the broad-line region (BLR) in active galactic nuclei (AGNs) with ultrafast outflows (UFOs). Mrk 79 is a radio-quiet AGN with UFOs and warm absorbers and has been monitored by three reverberation mapping (RM) campaigns, but its BLR kinematics are not yet understood. In this paper, we report the results from a new RM campaign of Mrk 79, which was undertaken with the Lijiang 2.4 m telescope. Mrk 79 appears to come out the faint state, with the mean flux approximately a magnitude fainter than the historical record. We successfully measured the lags of the broad emission lines including Hβ λ4861, Hγ λ4340, He ii λ4686, and He i λ5876 with respect to the varying AGN continuum. Based on the broad Hβ λ4861 line, we measured a black hole mass of

M

•

=

5.13

−
1.55

+
1.57

×

10

7

M

⊙

, and an estimated accretion rate of

M

̇

•

=
(
0.05
±
0.02
)

L

Edd

c

−
2

, indicating that Mrk 79 is a sub-Eddington accretor. We found that Mrk 79 deviates from the canonical Radius−Luminosity relationship. The marginal blueshift of the broad He ii λ4686 line detected from the rms spectrum indicates outflow of high-ionization gas. The velocity-resolved lag profiles of the broad Hγ λ4340, Hβ λ4861, and He i λ5876 lines show similar signatures such that the largest lag occurs in the red wing of the lines and then the lag decreases to both sides. These signatures may suggest that the BLR of Keplerian motion probably exists as outflow gas motion. All findings including UFOs, warm absorbers, and the kinematics of high- and low-ionization BLR, may provide indirect evidence that the BLR of Mrk 79 probably originates from a disk wind.
Assembly challenges with Flip Chip multi-die and interposer-based SiP Modules
Authors: Singh Akhilesh K , Sullivan Kevin M , Leal George R , Gong Tony 
Published: December 2019

Abstract
System in Package (SiP) modules provide integrated functionalities (processor, memory, power, etc.) in a small form factor as compared to PCB based individually laid out packages and passives. SiP modules face assembly related challenges as the complexity of packages increases (multi die, large number of passives, through mold via interposer for external memory, convergence of different technologies). This paper describes assembly challenges associated with a multi-die flip chip (processor, memory and power) module with plastic interposer for external Package-on-Package (PoP) memory. The prototype test package with three flip chip die was processed using different bump structures with bump height variation and differences in coplanarity. The underfill dispense pattern was optimized to eliminate underfill creep to the top of passive components that could lead to interfacial delamination. The interposer solder had no reliability risk due to the added mechanical strength of the underfill. Laser ablation formed through mold vias (TMV) on top of the interposers to connect to a package on package memory device. Partially defined TMV opening profile, adjacent solder bridging, formation of cold joint due to poor coplanarity, and foreign material contamination concerns were mitigated by tightening design and process parameters for flip chip attach (bump shorting and cold joint), underfill (interposer tilt, voids, material creep, dispense pattern, volume), interposer (tilt, warpage, solder voids), TMV laser ablation process (exposed Cu, depth, width), and mounting of passives components (topography, misalignment, cap solder volume).
Prospects for automotive SiP modules applying IC assembly and packaging technology
Authors: Furukawa Tomohiro , Kasuga Takahiro , Umehara Masato , Tamadate Yuka 
Published: December 2019

Abstract
We develop a package that ensures quality complying with AEC-Q 100 Grade 2 which is in-vehicle quality from various flip chip mounting methods and bump sealing technology with underfill resin and mold resin. FC CSP with heat spreader mounted on the product which has started mass production since last year is in the lineup, The heat dissipation can be improved by attaching the heat spreader directly to the chip backside which are heat sources and the Thermal Interface Material (TIM), using our assembly technology of flip chip mounting and molding the periphery while exposing the chip backside. By adjusting the Coefficient of Thermal Expansion (CTE) and thickness of the material, we realize low warpage and low coplanarity at reflow temperature and product use temperature environment and reduce package displacement behavior, we will improve the secondary mountability to the motherboard and provide reliable packages. Furthermore, it can be applied to SiP modules.
It is also possible to construct multiple chip modules by mounting multiple ICs or placing low-passive components around them. We will consider heat spreader mounting on multiple ICs that generate heat, and metal coating on the entire SiP module to have a structure that achieves both heat dissipation and electromagnetic shielding as a future idea.