bluuebunny/crossref_metadata_2025_split huggingface dataset:
An HST Survey of Protostellar Outflow Cavities: Does Feedback Clear Envelopes?
Authors: Habel Nolan M. , Thomas Megeath S. , Jon Booker Joseph , Fischer William J. , Kounkel Marina , Poteet Charles , Furlan Elise , Stutz Amelia , Manoj P. , Tobin John J. , Nagy Zsofia , Pokhrel Riwaj , Watson Dan 
Published: April 2021

Abstract
We study protostellar envelope and outflow evolution using Hubble Space Telescope NICMOS or WFC3 images of 304 protostars in the Orion molecular clouds. These near-IR images resolve structures in the envelopes delineated by the scattered light of the central protostars with 80 au resolution, and they complement the 1.2 μm to 870 μm spectral energy distributions (SEDs) obtained with the Herschel Orion Protostar Survey program. Based on their 1.60 μm morphologies, we classify the protostars into five categories: nondetections, point sources without nebulosity, bipolar cavity sources, unipolar cavity sources, and irregulars. We find point sources without associated nebulosity are the most numerous, and show through monochromatic Monte Carlo radiative transfer modeling that this morphology occurs when protostars are observed at low inclinations or have low envelope densities. We also find that the morphology is correlated with the SED-determined evolutionary class, with Class 0 protostars more likely to be nondetections, Class I protostars to show cavities, and flat-spectrum protostars to be point sources. Using an edge detection algorithm to trace the projected edges of the cavities, we fit power laws to the resulting cavity shapes, thereby measuring the cavity half-opening angles and power-law exponents. We find no evidence for the growth of outflow cavities as protostars evolve through the Class I protostar phase, in contradiction with previous studies of smaller samples. We conclude that the decline of mass infall with time cannot be explained by the progressive clearing of envelopes by growing outflow cavities. Furthermore, the low star formation efficiency inferred for molecular cores cannot be explained by envelope clearing alone.
The TeV Cosmic-Ray Bump: A Message from the Epsilon Indi or Epsilon Eridani Star?
Authors: Malkov Mikhail A. , Moskalenko Igor V. 
Published: April 2021

Abstract
A recently observed bump in the cosmic-ray (CR) spectrum from 0.3 to 30 TV is likely caused by a stellar bow shock that reaccelerates preexisting CRs, which further propagate to the Sun along the magnetic field lines. Along their way, these particles generate an Iroshnikov–Kraichnan (I-K) turbulence that controls their propagation and sustains the bump. Ad hoc fitting of the bump shape requires six adjustable parameters. Our model requires none, merely depending on three physical unknowns that we constrain using the fit. These are the shock Mach number, M, its size, l
⊥, and the distance to it, ζ
obs. Altogether, they define the bump rigidity R
0. With M ≈ 1.5–1.6 and R
0 ≈ 4.4 TV, the model fits the data with ≈0.08% accuracy. The fit critically requires the I-K spectrum predicted by the model and rules out the alternatives. These attributes of the fit make an accidental agreement highly unlikely. In turn, the R
0 and M derived from the fit impose the distance−size relation on the shock: ζ
obs(pc) ∼

. For sufficiently large bow shocks, l
⊥ = 10−3−10−2 pc, we find the distance of ζ
obs = 3–10 pc. Three promising stars in this range are the Scholz’s Star at 6.8 pc, Epsilon Indi at 3.6 pc, and Epsilon Eridani at 3.2 pc. Based on their current positions and velocities, we propose that Epsilon Indi and Epsilon Eridani can produce the observed spectral bump. Moreover, Epsilon Eridani’s position is only ∼67 off of the magnetic field direction in the solar neighborhood, which also changes the CR arrival direction distribution. Given the proximity of these stars, the bump appearance may change in a relatively short time.
Time Delay of Mg ii Emission Response for the Luminous Quasar HE 0435-4312: toward Application of the High-accretor Radius–Luminosity Relation in Cosmology
Authors: Zajaček Michal , Czerny Bożena , Martinez–Aldama Mary Loli , Rałowski Mateusz , Olejak Aleksandra , Przyłuski Robert , Panda Swayamtrupta , Hryniewicz Krzysztof , Śniegowska Marzena , Naddaf Mohammad-Hassan , Prince Raj , Pych Wojtek , Pietrzyński Grzegorz , Sobrino Figaredo Catalina , Haas Martin , Średzińska Justyna , Krupa Magdalena , Kurcz Agnieszka , Udalski Andrzej , Karas Vladimír , Sarna Marek , Worters Hannah L. , Sefako Ramotholo R. , Genade Anja 
Published: April 2021

Abstract
Using six years of spectroscopic monitoring of the luminous quasar HE 0435-4312 (z = 1.2231) with the Southern African Large Telescope, in combination with photometric data (CATALINA, OGLE, SALTICAM, and BMT), we determined a rest-frame time delay of

days between the Mg ii broad-line emission and the ionizing continuum using seven different time-delay inference methods. Time-delay artifact peaks and aliases were mitigated using the bootstrap method and prior weighting probability function, as well as by analyzing unevenly sampled mock light curves. The Mg ii emission is considerably variable with a fractional variability of ∼5.4%, which is comparable to the continuum variability (∼4.8%). Because of its high luminosity (L
3000 = 1046.4 erg s−1), the source is beneficial for a further reduction of the scatter along the Mg ii-based radius–luminosity relation and its extended versions, especially when the highly accreting subsample that has an rms scatter of ∼0.2 dex is considered. This opens up the possibility of using the high-accretor Mg ii-based radius–luminosity relation for constraining cosmological parameters. With the current sample of 27 reverberation-mapped sources, the best-fit cosmological parameters (Ωm, ΩΛ) = (0.19; 0.62) are consistent with the standard cosmological model within the 1σ confidence level.
More Variable Quasars Have Stronger Emission Lines
Authors: Kang Wen-Yong , Wang Jun-Xian , Cai Zhen-Yi , Ren Wen-Ke 
Published: April 2021

Abstract
UV/optical variation, likely driven by accretion disk turbulence, is a defining characteristic of type 1 active galactic nuclei and quasars. In this work we investigate an interesting consequence of such turbulence using quasars in Sloan Digital Sky Survey Stripe 82 for which the measurements of the UV/optical variability amplitude are available from ∼10 yr long light curves. We discover positive correlations between the UV/optical variability amplitude σ
rms and equivalent widths of C iv, Mg ii, and [O iii]5007 emission lines. Such correlations remain statistically robust through partial correlation analyses, i.e., after controlling the effects of other variables including bolometric luminosity, central supermassive black hole mass, Eddington ratio, and redshift. This, for the first time, indicates a causal link between disk turbulence and emission line production. We propose two potential underlying mechanisms, both of which may be involved: (1) quasars with stronger disk turbulence have on average a bluer/harder broadband spectral energy distribution, an expected effect of the disk thermal fluctuation model; (2) stronger disk turbulence could lead to the launch of emission line regions with larger covering factors.
Neutral versus Ion Line Widths in Barnard 5: Evidence for Penetration by Magnetohydrodynamic Waves
Authors: Pineda Jaime E. , Schmiedeke Anika , Caselli Paola , Stahler Steven W. , Frayer David T. , Church Sarah E. , Harris Andrew I. 
Published: April 2021

Abstract
Dense cores are the final place where turbulence is dissipated. It has been proposed from theoretical arguments that the nonthermal velocity dispersion should be narrower both for molecular ions (compared to neutrals) and for transitions with higher critical densities. To test these hypotheses, we compare the velocity dispersion of

(1–0) (

= 6 × 104

) and

(

= 2 × 103

), in the dense core Barnard 5. We analyze well-resolved and high signal-to-noise observations of

(1,1) and (2,2) obtained with combining Robert C. Byrd Green Bank Telescope (GBT) and Very Large Array (VLA) data, and

(1–0) obtained with GBT Argus, which present a similar morphology. Surprisingly, the nonthermal velocity dispersion of the ion is systematically higher than that of the neutral by 20%. The derived sonic Mach number,

, has peak values

and

for

and

, respectively. This observed difference may indicate that the magnetic field even deep within the dense core is still oscillating, as it is in the turbulent region outside the core. The ions should be more strongly dynamically coupled to this oscillating field than the neutrals, thus accounting for their broader line width. If corroborated by further observations, this finding would shed additional light on the transition to quiescence in dense cores.
A Coplanar Circumbinary Protoplanetary Disk in the TWA 3 Triple M Dwarf System
Authors: Czekala Ian , Ribas Álvaro , Cuello Nicolás , Chiang Eugene , Macías Enrique , Duchêne Gaspard , Andrews Sean M. , Espaillat Catherine C. 
Published: April 2021

Abstract
We present sensitive ALMA observations of TWA 3, a nearby, young (∼10 Myr) hierarchical system composed of three pre-main-sequence M3–M4.5 stars. For the first time, we detected 12CO and 13CO J = 2–1 emissions from the circumbinary protoplanetary disk around TWA 3A. We jointly fit the protoplanetary disk velocity field, stellar astrometric positions, and stellar radial velocities to infer the architecture of the system. The Aa and Ab stars (0.29 ± 0.01 M
⊙ and 0.24 ± 0.01 M
⊙, respectively) comprising the tight (P = 35 days) eccentric (e = 0.63 ± 0.01) spectroscopic binary are coplanar with their circumbinary disk (misalignment <6° with 68% confidence), similar to other short-period binary systems. From models of the spectral energy distribution, we found the inner radius of the circumbinary disk (r
inner = 0.50–0.75 au) to be consistent with theoretical predictions of dynamical truncation r
cav/a
inner ≈ 3. The outer orbit of the tertiary star B (0.40 ± 0.28 M
⊙, a ∼ 65 ± 18 au, e = 0.3 ± 0.2) is not as well constrained as the inner orbit; however, orbits coplanar with the A system are still preferred (misalignment < 20°). To better understand the influence of the B orbit on the TWA 3A circumbinary disk, we performed SPH simulations of the system and found that the outer edge of the gas disk (r
outer = 8.5 ± 0.2 au) is most consistent with truncation from a coplanar, circular, or moderately eccentric orbit, supporting the preference from the joint orbital fit.
GASP XXXIV: Unfolding the Thermal Side of Ram Pressure Stripping in the Jellyfish Galaxy JO201
Authors: Campitiello M. Giulia , Ignesti Alessandro , Gitti Myriam , Brighenti Fabrizio , Radovich Mario , Wolter Anna , Tomičić Neven , Bellhouse Callum , Poggianti Bianca M. , Moretti Alessia , Vulcani Benedetta , Jaffé Yara L. , Paladino Rosita , Müller Ancla , Fritz Jacopo , Lourenço Ana C. C. , Gullieuszik Marco 
Published: April 2021

Abstract
X-ray studies of jellyfish galaxies play a crucial role in understanding the interactions between the interstellar medium (ISM) and the intracluster medium (ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining archival Chandra observations, Multi Unit Spectroscopic Explorer Hα cubes, and maps of the emission fraction of the diffuse ionized gas, we investigated both its high-energy spectral properties and the spatial correlation between its X-ray and optical emissions. The X-ray emission of JO201 is provided by both the Compton-thick active galactic nucleus (L

= 2.7 · 1041 erg s−1, not corrected for intrinsic absorption) and an extended component (L

1.9–4.5 · 1041 erg s−1) produced by a warm plasma (kT

keV), whose luminosity is higher than expected from the observed star formation (L

3.8 · 1040erg s−1). The spectral analysis showed that the X-ray emission is consistent with the thermal cooling of hot plasma. These properties are similar to the ones found in other jellyfish galaxies showing extended X-ray emission. A point-to-point analysis revealed that this X-ray emission closely follows the ISM distribution, whereas CLOUDY simulations proved that the ionization triggered by this warm plasma would be able to reproduce the [O i]/Hα excess observed in JO201. We conclude that the galactic X-ray emitting plasma originates on the surface of the ISM as a result of the ICM–ISM interplay. This process would entail the cooling and accretion of the ICM onto the galaxy, which could additionally fuel the star formation, and the emergence of [O i]/Hα excess in the optical spectrum.
Outflows from Super Star Clusters in the Central Starburst of NGC 253
Authors: Levy Rebecca C. , Bolatto Alberto D. , Leroy Adam K. , Emig Kimberly L. , Gorski Mark , Krieger Nico , Lenkić Laura , Meier David S. , Mills Elisabeth A. C. , Ott Jürgen , Rosolowsky Erik , Tarantino Elizabeth , Veilleux Sylvain , Walter Fabian , Weiß Axel , Zwaan Martin A. 
Published: April 2021

Abstract
Young massive clusters play an important role in the evolution of their host galaxies, and feedback from the high-mass stars in these clusters can have profound effects on the surrounding interstellar medium. The nuclear starburst in the nearby galaxy NGC 253 at a distance of 3.5 Mpc is a key laboratory in which to study star formation in an extreme environment. Previous high-resolution (1.9 pc) dust continuum observations from the Atacama Large Millimeter/submillimeter Array (ALMA) discovered 14 compact, massive super star clusters (SSCs) still in formation. We present here ALMA data at 350 GHz with 28 mas (0.5 pc) resolution. We detect blueshifted absorption and redshifted emission (P-Cygni profiles) toward three of these SSCs in multiple lines, including CS 7−6 and H13CN 4−3, which represent direct evidence for previously unobserved outflows. The mass contained in these outflows is a significant fraction of the cluster gas masses, which suggests we are witnessing a short but important phase. Further evidence of this is the finding of a molecular shell around the only SSC visible at near-IR wavelengths. We model the P-Cygni line profiles to constrain the outflow geometry, finding that the outflows must be nearly spherical. Through a comparison of the outflow properties with predictions from simulations, we find that none of the available mechanisms completely explains the observations, although dust-reprocessed radiation pressure and O star stellar winds are the most likely candidates. The observed outflows will have a very substantial effect on the clusters’ evolution and star formation efficiency.
Emerging Dimming as Coronal Heating Episodes
Authors: Payne Anna V. , Sun 孙 Xudong 旭东 
Published: April 2021

Abstract
Emerging dimming occurs in isolated solar active regions (ARs) during the early stages of magnetic flux emergence. Observed by the Atmospheric Imaging Assembly, it features a rapid decrease in extreme-ultraviolet (EUV) emission in the 171 Å channel images, and a simultaneous increase in the 211 Å images. Here, we analyze the coronal thermodynamic and magnetic properties to probe its physical origin. We calculate the time-dependent differential emission measures for a sample of 18 events between 2010 and 2012. The emission measure (EM) decrease in the temperature range

is well correlated with the EM increase in

over eight orders of magnitude. This suggests that the coronal plasma is being heated from the quiet-Sun, sub-MK temperature to 1–2 MK, more typical for ARs. Potential field extrapolation indicates significant change in the local magnetic connectivity: the dimming region is now linked to the newly emerged flux via longer loops. We conclude that emerging dimming is likely caused by coronal heating episodes, powered by reconnection between the emerging and the ambient magnetic fields.
Planck Cold Clumps in the λ Orionis Complex. III. A Chemical Probe of Stellar Feedback on Cores in the λ Orionis Cloud
Authors: Yi Hee-Weon , Lee Jeong-Eun , Kim Kee-Tae , Liu Tie , Lim Beomdu , Tatematsu Ken’ichi ,   JCMT Large Program “SCOPE” collaboration
Published: April 2021

Abstract
Massive stars have a strong impact on their local environments. However, how stellar feedback regulates star formation is still under debate. In this context, we studied the chemical properties of 80 dense cores in the Orion molecular cloud complex composed of the Orion A (39 cores), B (26 cores), and λ Orionis (15 cores) clouds using multiple molecular line data taken with the Korean Very Long Baseline Interferometry Network 21 m telescopes. The λ Orionis cloud has an H ii bubble surrounding the O-type star λ Ori, and hence it is exposed to the ultraviolet (UV) radiation field of the massive star. The abundances of C2H and HCN, which are sensitive to UV radiation, appear to be higher in the cores in the λ Orionis cloud than in those in the Orion A and B clouds, while the HDCO to H2CO abundance ratios show the opposite trend, indicating warmer conditions in the λ Orionis cloud. The detection rates of dense gas tracers such as the N2H+, HCO+, and H13CO+ lines are also lower in the λ Orionis cloud. These chemical properties imply that the cores in the λ Orionis cloud are heated by UV photons from λ Ori. Furthermore, the cores in the λ Orionis cloud do not show any statistically significant excess in the infall signature of HCO+ (1–0), unlike those in the Orion A and B clouds. Our results support the idea that feedback from massive stars impacts star formation in a negative way by heating and evaporating dense materials, as in the λ Orionis cloud.
Which is the Prognostic Value of the Mini Mental State Examination Test in Surgical Oncology?
Authors: Nikova Alexandrina , Vlotinou Penelope , Karanikas Michael , Tsoleridis Тheofilos , Bakalinis Emmanuil , Tselepidis Vasilios , Ntatsis Konstantinos 
Published: April 2021

Introduction: Cancer patients are usually subjected to numerous surgeries during their course of treatment. Recent studies suggest that anesthetic drugs such as propofol, benzodiazepines, and opioids are linked to cognitive impairment.
Aim: The aim of the study was to show and compare the cognitive function of oncology patients who have undergone surgery and have been sedated with propofol, fentanyl and benzodiazepines.
Materials and methods: In order to determine whether the cognition of oncological patients is being impaired, a mini-mental state examination (MMSE) test was obtained 6 to 24 hours pre- and postoperatively for the duration of one month from 8 eligible oncological patients and 7 non-oncological ones. Afterwards, the data were statistically processed with SPSS version 25.0 (Chicago, Ill. the USA).
Results: The analysis shows that there is statistically significant difference in the preoperative MMSE scores between oncological and non-oncological patients.&nbsp;
Conclusions: Oncological patients compound a sensitive group for cognitive dysfunction, and indeed, MMSE test could be useful for cognitive evaluation. The present sample, however, is small, and the results could not be generalized. Therefore a more extensive study is needed.
Final fusion in a complex of surgical treatment for early onset scoliosis
Authors: Mikhaylovskiy Mikhail V. , Ryabykh Sergey O. , Suzdalov Vasiliy A. , Filatov Egor Y. , Savin Dmitry M. , Chernyadieva Maria A. , Alshevskaya Alina A. 
Published: April 2021

Introduction: Surgical treatment of early onset scoliosis (EOS) is one of the most challenging problems of spine surgery and includes staged distraction and final fusion at the end of skeletal maturity that remains debatable.
Aim: The objective of the review is to evaluate the efficacy of final fusion following staged distraction with VEPTR instrumentation in patients with EOS.
Materials and methods: Outcomes of multi-staged operative treatment of 37 patients with EOS of different etiology were reviewed. Medical records and radiographs of the patients were retrospectively analyzed. Standing postero-anterior and lateral spine radiographs were used for the spinal radiologic assessment before and after each stage of distraction-based treatment, before and after final fusion and at the last follow-up.
Results: The mean age of patients at baseline was 5.2 years and the mean age at final fusion was 13.9 years. All patients demonstrated decrease in the angle of primary (from 81.5&deg; to 51.6&deg;) and secondary (from 59.3&deg; to 37.8&deg;) curves, increase of the height and normalized body balance. The mean height increased from 104.8 cm to 141.0 cm, and the mean weight increased from 15 kg to 35 kg throughout the treatment period. The height of the thoracic and lumbar vertebra (Th1-S1) increased from 245 mm to 340 mm, and that of the&nbsp;thoracic vertebra &ndash; from 136 mm to 193 mm. There was a mean of 2.3 complications per patient during distraction performed in a staged manner, and they were arrested during elective procedures. There were 7 (19%) complications after final fusion that required 6 (16%) unplanned revisions. Radiologic evidence of spontaneous autofusion was seen in the lumbar spine of the patients with the inferior&nbsp;anchor at the lumbar vertebra.
Conclusions: Multi-staged pediatric surgeries performed in the first decade of life facilitate radical changes in the natural history of progressive scoliosis and ensure satisfactory functional and cosmetic results despite multiple difficulties and complications. The VEPTR instrumentation used for the thoracic curve is unlikely to result in the spinal fusion of the major arch and this is the cause for the use of third-generation instrumented final spinal fusion in the patients.&nbsp;