bluuebunny/crossref_metadata_2025_split huggingface dataset:
SILVERRUSH. VIII. Spectroscopic Identifications of Early Large-scale Structures with Protoclusters over 200 Mpc at z ∼ 6–7: Strong Associations of Dusty Star-forming Galaxies
Authors: Harikane Yuichi , Ouchi Masami , Ono Yoshiaki , Fujimoto Seiji , Donevski Darko , Shibuya Takatoshi , Faisst Andreas L. , Goto Tomotsugu , Hatsukade Bunyo , Kashikawa Nobunari , Kohno Kotaro , Hashimoto Takuya , Higuchi Ryo , Inoue Akio K. , Lin Yen-Ting , Martin Crystal L. , Overzier Roderik , Smail Ian , Toshikawa Jun , Umehata Hideki , Ao Yiping , Chapman Scott , Clements David L. , Im Myungshin , Jing Yipeng , Kawaguchi Toshihiro , Lee Chien-Hsiu , Lee Minju M. , Lin Lihwai , Matsuoka Yoshiki , Marinello Murilo , Nagao Tohru , Onodera Masato , Toft Sune , Wang Wei-Hao 
Published: October 2019

Abstract
We have obtained three-dimensional maps of the universe in ∼200 × 200 × 80 comoving Mpc3 (cMpc3) volumes each at z = 5.7 and 6.6 based on a spectroscopic sample of 179 galaxies that achieves ≳80% completeness down to the Lyα luminosity of

, based on our Keck and Gemini observations and the literature. The maps reveal filamentary large-scale structures and two remarkable overdensities made out of at least 44 and 12 galaxies at z = 5.692 (z57OD) and z = 6.585 (z66OD), respectively, making z66OD the most distant overdensity spectroscopically confirmed to date, with >10 spectroscopically confirmed galaxies. We compare spatial distributions of submillimeter galaxies at z ≃ 4–6 with our z = 5.7 galaxies forming the large-scale structures, and detect a 99.97% signal of cross-correlation, indicative of a clear coincidence of dusty star-forming galaxy and dust-unobscured galaxy formation at this early epoch. The galaxies in z57OD and z66OD are actively forming stars with star-formation rates (SFRs) ≳5 times higher than the main sequence, and particularly the SFR density in z57OD is 10 times higher than the cosmic average at the redshift (a.k.a. the Madau-Lilly plot). Comparisons with numerical simulations suggest that z57OD and z66OD are protoclusters that are progenitors of the present-day clusters with halo masses of ∼1014
M
⊙.
Turbulence Driven by Stellar Jets, the Possibility and the Efficiency
Authors: Sheikhnezami Somayeh , Abgharian-Afoushteh Mohsen 
Published: October 2019

Abstract
We investigate the feedback of the stellar jets on the surrounding interstellar gas based on 2D and 3D simulations applying HD and MHD modules of the PLUTO 4.2 code. The main question we address is whether the stellar jet can be considered as a turbulence driver into the interstellar gas. In addition, we investigate the most effective circumstances in which the driven turbulence is larger and can survive for a longer timescale in the ambient gas. We present a case study of different parameter runs including the jet Mach number, the initial jet velocity field, the background magnetic field geometries and the interacting jets. We also study the environmental effects on the jet-gas interaction by considering the non-homogeneous surrounding gas containing the clumps in the model setup. Among different setups, we find (1) a higher jet Mach number, (2) a rotating jet, (3) a jet propagating in a magnetized environment, (4) a jet propagating in a non-homogeneous environment, and (5) the interacting jets produce more fluctuations and random motions in the entrained gas, which can survive for a longer timescale. In addition, we perform the 3D simulations of jet-ambient gas interaction and we find that the amount of (subsonic–supersonic) fluctuation increases compared to the axisymmetric run, and the entrained gas gains higher velocities in a 3D run. In total, we confirm the previous finding that the stellar jets can transfer the turbulence on neighboring regions and are not sufficient drivers of the large-scale supersonic turbulence in molecular clouds.
Relativistic Astronomy. III. Test of Special Relativity via Doppler Effect
Authors: Yang Yuan-Pei , Zhu Jin-Ping , Zhang Bing 
Published: October 2019

Abstract
The “Breakthrough Starshot” program is planning to send transrelativistic probes to travel to nearby stellar systems within decades. Because the probe velocity is designed to be a good fraction of the light speed, Zhang & Li recently proposed that these transrelativistic probes can be used to study astronomical objects and to test special relativity. In this work, we propose some methods to test special relativity and constrain photon mass using the Doppler effect with the images and spectral features of astronomical objects as observed in the transrelativistic probes. We introduce more general theories to set up the framework of testing special relativity, including the parametric general Doppler effect and the Doppler effect with massive photons. We find that by comparing the spectra of a certain astronomical object, one can test Lorentz invariance and constrain photon mass. Additionally, using the imaging and spectrograph capabilities of transrelativistic probes, one can test time dilation and constrain photon mass. For a transrelativistic probe with velocity v ∼ 0.2c, aperture D ∼ 3.5 cm, and spectral resolution R ∼ 100 (or 1000), we find that the probe velocity uncertainty can be constrained to σ

v
∼ 0.01c (or 0.001c), and the time dilation factor uncertainty can be constrained to

(or 0.001), where

is the time dilation factor and γ is the Lorentz factor. Meanwhile, the photon mass limit is set to m

γ
≲ 10−33 g, which is slightly lower than the energy of the optical photon.
Spectrophotometric Redshifts for z ∼ 1 Galaxies and Predictions for Number Densities with WFIRST and Euclid
Authors: Joshi Bhavin A. , Cohen Seth , Windhorst Rogier A. , Jansen Rolf , Pirzkal Norbert , Hathi Nimish P. 
Published: October 2019

Abstract
We investigate the accuracy of 4000 Å/Balmer-break based redshifts by combining Hubble Space Telescope (HST) grism data with photometry. The grism spectra are from the Probing Evolution And Reionization Spectroscopically survey with HST using the G800L grism on the Advanced Camera for Surveys. The photometric data come from a compilation by the 3D-HST collaboration of imaging from multiple surveys (notably, the Cosmic Assembly Near-infrared Deep Extragalactic Survey (CANDELS) and 3D-HST). We show evidence that spectrophotometric redshifts (SPZs) typically improve the accuracy of photometric redshifts by ∼17%–60%. Our SPZ method is a template-fitting-based routine that accounts for correlated data between neighboring points within grism spectra via the covariance matrix formalism and also accounts for galaxy morphology along the dispersion direction. We show that the robustness of the SPZ is directly related to the fidelity of the D4000 measurement. We also estimate the accuracy of continuum-based redshifts, i.e., for galaxies that do not contain strong emission lines, based on the grism data alone (

). Given that future space-based observatories like Wide Field InfraRed Survey Telescope and Euclid will spend a significant fraction of time on slitless spectroscopic observations, we estimate number densities for objects with

. We predict ∼700–4400 galaxies degree−2 for galaxies with D4000 > 1.1 and

to a limiting depth of i

AB
= 24 mag. This is especially important in the absence of an accompanying rich photometric data set like the existing one for the CANDELS fields, where redshift accuracy from future surveys will rely only on the presence of a feature like the 4000 Å/Balmer breaks or the presence of emission lines within the grism spectra.
A Triple AGN in a Mid-infrared Selected Late-stage Galaxy Merger
Authors: Pfeifle Ryan W. , Satyapal Shobita , Manzano-King Christina , Cann Jenna , Sexton Remington O. , Rothberg Barry , Canalizo Gabriela , Ricci Claudio , Blecha Laura , Ellison Sara L. , Gliozzi Mario , Secrest Nathan J. , Constantin Anca , Harvey Jenna B. 
Published: October 2019

Abstract
The coevolution of galaxies and the supermassive black holes (SMBHs) at their centers via hierarchical galaxy mergers is a key prediction of ΛCDM cosmology. As gas and dust are funneled to the SMBHs during the merger, the SMBHs light up as active galactic nuclei (AGNs). In some cases, a merger of two galaxies can encounter a third galaxy, leading to a triple merger, which would manifest as a triple AGN if all three SMBHs are simultaneously accreting. Using high spatial resolution X-ray, near-IR, and optical spectroscopic diagnostics, we report here a compelling case of an AGN triplet with mutual separations <10 kpc in the advanced merger SDSS J084905.51+111447.2 at z = 0.077. The system exhibits three nuclear X-ray sources, optical spectroscopic line ratios consistent with AGN in each nucleus, a high excitation near-IR coronal line in one nucleus, and broad Paα detections in two nuclei. Hard X-ray spectral fitting reveals a high column density along the line of sight, consistent with the picture of late-stage mergers hosting heavily absorbed AGNs. Our multiwavelength diagnostics support a triple AGN scenario, and we rule out alternative explanations such as star formation activity, shock-driven emission, and emission from fewer than three AGN. The dynamics of gravitationally bound triple SMBH systems can dramatically reduce binary SMBH inspiral timescales, providing a possible means to surmount the “Final Parsec Problem.” AGN triplets in advanced mergers are the only observational forerunner to bound triple SMBH systems and thus offer a glimpse of the accretion activity and environments of the AGNs prior to the gravitationally bound triple phase.
Toward a Model-independent Measurement of the Halo Mass Function with Observables
Authors: Dong Fuyu , Zhang Jun , Yang Xiaohu , Zhang Jiajun , Luo Wentao 
Published: October 2019

Abstract
In the CDM paradigm, the halo mass function is a sensitive probe of the cosmic structure. In observations, halo mass is typically estimated from its relation with other observables. The resulting halo mass function is subject to systematic bias, such as the Eddington bias, due to the scatter or uncertainty in the observable–mass relation. Exact correction for the bias is not easy, as predictions for the observables are typically model-dependent in simulations. In this paper, we point out an interesting feature in the halo mass function of the concordance ΛCDM model: the total halo mass within each evenly spaced logarithmic mass bin is approximately the same over a large mass range. We show that this property allows us to construct an almost bias-free halo mass function using only an observable (as a halo mass estimator) and stacked weak lensing measurements as long as the scatter between the true halo mass and the observable-inferred mass has a stable form in logarithmic units. The method is not sensitive to the form of the mass–observable relation. We test the idea using cosmological simulations, and show that the method performs very well for realistic observables.
A Tale of Two Clusters: An Analysis of Gas-phase Metallicity and Nebular Gas Conditions in Proto-cluster Galaxies at z ∼ 2
Authors: Alcorn Leo Y. , Gupta Anshu , Tran Kim-Vy , Kacprzak Glenn G. , Yuan Tiantian , Cohn Jonathan , Forrest Ben , Glazebrook Karl , Harshan Anishya , Kewley Lisa J. , Labbé Ivo , Nanayakkara Themiya , Papovich Casey , Spitler Lee R. , Straatman Caroline M. S. 
Published: October 2019

Abstract
The ZFIRE survey has spectroscopically confirmed two proto-clusters using the MOSFIRE instrument on Keck I: one at z = 2.095 in COSMOS and another at z = 1.62 in UKIRT Infrared Deep Sky Survey (UDS). Here, we use an updated ZFIRE data set to derive the properties of ionized gas regions of proto-cluster galaxies by extracting fluxes from emission lines Hβ 4861 Å, [O iii] 5007 Å, Hα 6563 Å, [N ii] 6585 Å, and [S ii] 6716,6731 Å. We measure gas-phase metallicity of members in both proto-clusters using two indicators, including a strong-line indicator relatively independent of the ionization parameter and electron density. Proto-cluster and field galaxies in both UDS and COSMOS lie on the same Mass–Metallicity Relation with both metallicity indicators. We compare our results to recent IllustrisTNG results, which report no significant gas-phase metallicity offset between proto-cluster and field galaxies until z = 1.5. This is in agreement with our observed metallicities, where no offset is measured between proto-cluster and field populations. We measure tentative evidence from stacked spectra that indicate UDS high-mass proto-cluster and field galaxies have differing [O iii]/Hβ ratios; however, these results are dependent on the sample size of the high-mass stacks.
Feature Ranking of Active Region Source Properties in Solar Flare Forecasting and the Uncompromised Stochasticity of Flare Occurrence
Authors: Campi Cristina , Benvenuto Federico , Massone Anna Maria , Bloomfield D. Shaun , Georgoulis Manolis K. , Piana Michele 
Published: October 2019

Abstract
Solar flares originate from magnetically active regions (ARs) but not all solar ARs give rise to a flare. Therefore, the challenge of solar flare prediction benefits from an intelligent computational analysis of physics-based properties extracted from AR observables, most commonly line-of-sight or vector magnetograms of the active region photosphere. For the purpose of flare forecasting, this study utilizes an unprecedented 171 flare-predictive AR properties, mainly inferred by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory (SDO/HMI) in the course of the European Union Horizon 2020 FLARECAST project. Using two different supervised machine-learning methods that allow feature ranking as a function of predictive capability, we show that (i) an objective training and testing process is paramount for the performance of every supervised machine-learning method; (ii) most properties include overlapping information and are therefore highly redundant for flare prediction; (iii) solar flare prediction is still—and will likely remain—a predominantly probabilistic challenge.
SN 2016coi (ASASSN-16fp): An Energetic H-stripped Core-collapse Supernova from a Massive Stellar Progenitor with Large Mass Loss
Authors: Terreran G. , Margutti R. , Bersier D. , Brimacombe J. , Caprioli D. , Challis P. , Chornock R. , Coppejans D. L. , Dong Subo , Guidorzi C. , Hurley K. , Kirshner R. , Migliori G. , Milisavljevic D. , Palmer D. M. , Prieto J. L. , Tomasella L. , Marchant P. , Pastorello A. , Shappee B. J. , Stanek K. Z. , Stritzinger M. D. , Benetti S. , Chen Ping , DeMarchi L. , Elias-Rosa N. , Gall C. , Harmanen J. , Mattila S. 
Published: October 2019

Abstract
We present comprehensive observations and analysis of the energetic H-stripped SN 2016coi (a.k.a. ASASSN-16fp), spanning the γ-ray through optical and radio wavelengths, acquired within the first hours to ∼420 days post explosion. Our observational campaign confirms the identification of He in the supernova (SN) ejecta, which we interpret to be caused by a larger mixing of Ni into the outer ejecta layers. By modeling the broad bolometric light curve, we derive a large ejecta-mass-to-kinetic-energy ratio (M
ej ∼ 4–7 M
⊙, E
k ∼ (7–8) × 1051 erg). The small [Ca ii] λλ7291,7324 to [O i] λλ6300,6364 ratio (∼0.2) observed in our late-time optical spectra is suggestive of a large progenitor core mass at the time of collapse. We find that SN 2016coi is a luminous source of X-rays (L
X > 1039 erg s−1 in the first ∼100 days post explosion) and radio emission (L
8.5 GHz ∼ 7 × 1027 erg s−1 Hz−1 at peak). These values are in line with those of relativistic SNe (2009bb, 2012ap). However, for SN 2016coi, we infer substantial pre-explosion progenitor mass loss with a rate

∼ (1–2) ×

and a sub-relativistic shock velocity v
sh ∼ 0.15c, which is in stark contrast with relativistic SNe and similar to normal SNe. Finally, we find no evidence for a SN-associated shock breakout γ-ray pulse with energy E

γ
> 2 × 1046 erg. While we cannot exclude the presence of a companion in a binary system, taken together, our findings are consistent with a massive single-star progenitor that experienced large mass loss in the years leading up to core collapse, but was unable to achieve complete stripping of its outer layers before explosion.
Exploring Exoplanet Cloud Assumptions in JWST Transmission Spectra
Authors: Mai Chuhong , Line Michael R. 
Published: October 2019

Abstract
Clouds are ubiquitous in extrasolar planet atmospheres and are critical to our understanding of planetary climate and chemistry. They also represent one of the greater challenges to overcome when trying to interpret transit transmission spectra of exoplanet atmospheres as their presence can inhibit precise constraints on atmospheric composition and thermal properties. In this work, we take a phenomenological approach toward understanding (1) our ability to constrain bulk cloud properties and (2) the impact of clouds on constraining various atmospheric properties as obtained through transmission spectroscopy with the James Webb Space Telescope (JWST). We do this by exploring retrievals of atmospheric and cloud properties for a generic “hot Jupiter” as a function of signal-to-noise ratio (S/N), JWST observing modes, and four different cloud parameterizations. We find that most key atmospheric and cloud inferences can be well constrained in the wavelength range (λ = 0.6–11 μm), with NIRCam (λ = 2.5–5 μm) being critical in inferring atmospheric properties and NIRISS + MIRI (λ = 0.6–2.5, 5–11 μm) being necessary for good constraints on cloud parameters. However, constraining the cloud abundance and therefore the total cloud mass requires an observable cloud base in the transit geometry. While higher S/N observations can place tighter constraints on major parameters such as temperature, metallicity, and cloud sedimentation, they are unable to eliminate strong degeneracies among cloud parameters. Our investigation of a generic “warm Neptune” with photochemical haze parameterization also shows promising results in constraining atmospheric and haze properties in the cooler temperature regime.
Chondrule Formation by the Jovian Sweeping Secular Resonance
Authors: Gong 龚 慕 Munan 南 , Zheng 郑 晓 Xiaochen 晨 , Lin 林 Douglas N. C. 潮 , Silsbee Kedron , Baruteau Clement , Mao 毛 淑 Shude 德 
Published: October 2019

Abstract
Chondrules are silicate spheroids found in meteorites, and they serve as important fossil records of the early solar system. In order to form chondrules, chondrule precursors must be heated to temperatures much higher than the typical conditions in the current asteroid belt. One proposed mechanism for chondrule heating is the passage through bow shocks of highly eccentric planetesimals in the protoplanetary disk in the early solar system. However, it is difficult for planetesimals to gain and maintain such high eccentricities. In this paper, we present a new scenario in which planetesimals in the asteroid belt region are excited to high eccentricities by the Jovian sweeping secular resonance in a depleting disk, leading to efficient formation of chondrules. We study the orbital evolution of planetesimals in the disk using semi-analytic models and numerical simulations. We investigate the dependence of eccentricity excitation on the planetesimal’s size, as well as the physical environment and the probability for chondrule formation. We find that 50–2000 km planetesimals can obtain eccentricities larger than 0.6 and cause effective chondrule heating. Most chondrules form in high-velocity shocks, in low-density gas, and in the inner disk. The fraction of chondrule precursors that become chondrules is about 4%–9% between 1.5 and 3 au. Our model implies that the disk depletion timescale is τ
dep ≈ 1 Myr, comparable to the age spread of chondrules, and that Jupiter formed before chondrules, no more than 0.7 Myr after the formation of calcium aluminum inclusions.
The Evolution of O i over 3.2 < z < 6.5: Reionization of the Circumgalactic Medium
Authors: Becker George D. , Pettini Max , Rafelski Marc , D’Odorico Valentina , Boera Elisa , Christensen Lise , Cupani Guido , Ellison Sara L. , Farina Emanuele Paolo , Fumagalli Michele , López Sebastian , Neeleman Marcel , Ryan-Weber Emma V. , Worseck Gábor 
Published: October 2019

Abstract
We present a survey for metal absorption systems traced by neutral oxygen over 3.2 < z < 6.5. Our survey uses Keck/ESI and VLT/X-Shooter spectra of 199 QSOs with redshifts up to 6.6. In total, we detect 74 O i absorbers, of which 57 are separated from the background QSO by more than 5000 km s−1. We use a maximum likelihood approach to fit the distribution of O i λ1302 equivalent widths in bins of redshift and from this determine the evolution in number density of absorbers with W
1302 > 0.05 Å, of which there are 49 nonproximate systems in our sample. We find that the number density does not monotonically increase with decreasing redshift, as would naively be expected from the buildup of metal-enriched circumgalactic gas with time. The number density over 4.9 < z < 5.7 is a factor of 1.7–4.1 lower (68% confidence) than that over 5.7 < z < 6.5, with a lower value at z < 5.7 favored with 99% confidence. This decrease suggests that the fraction of metals in a low-ionization phase is larger at z ∼ 6 than at lower redshifts. Absorption from highly ionized metals traced by C iv is also weaker in higher-redshift O i systems, supporting this picture. The evolution of O i absorbers implies that metal-enriched circumgalactic gas at z ∼ 6 is undergoing an ionization transition driven by a strengthening ultraviolet background. This in turn suggests that the reionization of the diffuse intergalactic medium may still be ongoing at or only recently ended by this epoch.
Brown Dwarf Atmospheres as the Potentially Most Detectable and Abundant Sites for Life
Authors: Lingam Manasvi , Loeb Abraham 
Published: October 2019

Abstract
We show that the total habitable volume in the atmospheres of cool brown dwarfs with effective temperatures of ∼250–350 K is possibly larger by 2 orders of magnitude than that of Earth-like planets. We also study the role of aerosols, nutrients, and photosynthesis in facilitating life in brown dwarf atmospheres. Our predictions might be testable through searches for spectral edges in the near-infrared and chemical disequilibrium in the atmospheres of nearby brown dwarfs that are either free-floating or within several au of stars. For the latter category, we find that the James Webb Space Telescope may be able to achieve a signal-to-noise ratio of ∼5 after a few hours of integration time per source for the detection of biogenic spectral features in ∼103 cool brown dwarfs.