bluuebunny/crossref_metadata_2025_split huggingface dataset:
How do supernova remnants cool? – I. Morphology, optical emission lines, and shocks
Authors: Makarenko Ekaterina I , Walch Stefanie , Clarke Seamus D , Seifried Daniel , Naab Thorsten , Nürnberger Pierre C , Rathjen Tim-Eric 
Published: May 2023

ABSTRACT
Supernovae (SNe) inject ∼1051 erg in the interstellar medium, thereby shocking and heating the gas. A substantial fraction of this energy is later lost via radiative cooling. We present a post-processing module for the flash code to calculate the cooling radiation from shock-heated gas using collisional excitation data from mappings v. When applying this tool to a simulated SN remnant (SNR), we find that most energy is emitted in the EUV. However, optical emission lines ([O iii], [N ii], [S ii], H α, H β) are usually best observable. Our shock detection scheme shows that [S ii] and [N ii] emissions arise from the thin shell surrounding the SNR, while [O iii], H $\rm \alpha$, and H $\rm \beta$ originate from the volume-filling hot gas inside the SNR bubble. We find that the optical emission lines are affected by the SNR’s complex structure and its projection on to the plane of the sky because the escaping line luminosity can be reduced by 10–80 per cent due to absorption along the line of sight. Additionally, the subtraction of contaminating background radiation is required for the correct classification of an SNR on the oxygen or sulphur BPT diagrams. The electron temperature and density obtained from our synthetic observations match well with the simulation but are very sensitive to the assumed metallicity.
First emergence of cold accretion and supermassive star formation in the early universe
Authors: Kiyuna Masaki , Hosokawa Takashi , Chon Sunmyon 
Published: May 2023

ABSTRACT
We investigate the first emergence of the so-called cold accretion, the accretion flows deeply penetrating a halo, in the early universe with cosmological N-body/SPH simulations. We study the structure of the accretion flow and its evolution within small haloes with ≲108 M⊙ with sufficiently high spatial resolutions down to ∼1 pc scale. While previous studies only follow the evolution for a short period after the primordial cloud collapse, we follow the long-term evolution until the cold accretion first appears, employing the sink particle method. We show that the cold accretion emerges when the halo mass exceeds ∼2.2 × 107 M⊙{(1 + z)/15}−3/2, the minimum halo masses above which the accretion flow penetrates haloes. We further continue simulations to study whether the cold accretion provides the dense shock waves, which have been proposed to give birth to supermassive stars (SMSs). We find that the accretion flow eventually hits a compact disc near the halo centre, creating dense shocks over a wide area of the disc surface. The resulting post-shock gas becomes dense and hot enough with its mass comparable to the Jeans mass MJ ∼ 104–5 M⊙, a sufficient amount to induce the gravitational collapse, leading to the SMS formation.
A geometric calibration of the tip of the red giant branch in the Milky Way using Gaia DR3
Authors: Dixon M , Mould J , Flynn C , Taylor E N , Lidman C , Duffy A R 
Published: May 2023

ABSTRACT
We use the latest parallaxes measurements from Gaia DR3 to obtain a geometric calibration of the tip of the red giant branch (TRGB) in Cousins I magnitudes as a standard candle for cosmology. We utilize the following surveys: SkyMapper DR3, APASS DR9, ATLAS Refcat2, and Gaia DR3 synthetic photometry to obtain multiple zero-point calibrations of the TRGB magnitude, $M_{I}^{TRGB}$. Our sample contains Milky Way halo stars at high galactic latitudes (|b| &gt; 36) where the impact of metallicity, dust, and crowding are minimized. The magnitude of the TRGB is identified using Sobel edge detection, but this approach introduced a systematic offset. To address this issue, we utilized simulations with parsec isochrones and showed how to calibrate and remove this bias. Applying our method within the colour range where the slope of the TRGB is relatively flat for metal-poor halo stars (1.55 &lt; (BP − RP) &lt; 2.25), we find a weighted average $M_{I}^{TRGB} = -4.042 \pm 0.041$ (stat) ±0.031 (sys) mag. A geometric calibration of the Milky Way TRGB has the benefit of being independent of other distance indicators and will help probe systematics in the local distance ladder, leading to improved measurements of the Hubble constant.
Observability of photoevaporation signatures in the dust continuum emission of transition discs
Authors: Picogna Giovanni , Schäfer Carolina , Ercolano Barbara , Rab Christian , Franz Rafael , Gárate Matías 
Published: May 2023

ABSTRACT
Photoevaporative disc winds play a key role in our understanding of circumstellar disc evolution, especially in the final stages, and they might affect the planet formation process and the final location of planets. The study of transition discs (i.e. discs with a central dust cavity) is central for our understanding of the photoevaporation process and disc dispersal. However, we need to distinguish cavities created by photoevaporation from those created by giant planets. Theoretical models are necessary to identify possible observational signatures of the two different processes, and models to find the differences between the two processes are still lacking. In this paper, we study a sample of transition discs obtained from radiation–hydrodynamic simulations of internally photoevaporated discs, and focus on the dust dynamics relevant for current Atacama Large Millimetre Array observations. We then compared our results with gaps opened by a super-Earth/giant planets, finding that the photoevaporated cavity steepness depends mildly on gap size, and it is similar to that of a ${1}\, {\rm M_J}$ planet. However, the dust density drops less rapidly inside the photoevaporated cavity compared to the planetary case due to the less efficient dust filtering. This effect is visible in the resulting spectral index, which shows a larger spectral index at the cavity edge and a shallower increase inside it with respect to the planetary case. The combination of cavity steepness and spectral index might reveal the true nature of transition discs.
Spatial eigenvalue problems for stars in hydrostatic equilibrium: Generalized Lane–Emden equations as boundary value problems
Authors: Van Gorder Robert A , Fisher Petra A 
Published: May 2023

ABSTRACT
We derive a generic spatial eigenvalue problem governing stars in hydrostatic equilibrium. Our approach generalizes the various Lane–Emden equations finding use over the past century, allowing for more general equations of state (EoS) while ensuring a stellar structure with finite size (without the need for artificial truncation of the radius). We show that the resulting stellar structure is encoded into two quantities: the eigenvalue, which determines the total size or mass of the star, and the density distribution, which encodes the internal structure. While our formalism recovers known results for polytrope and white dwarf EoS, we also study additional EoS, such as those incorporating excluded volumes or those calibrated through viral expansions. We obtain numerical values for the stellar structure under a variety of frameworks, comparing and contrasting stellar structure under different EoS. Interestingly, we show how different EoS can be calibrated to give solutions with the same stellar structure, highlighting the arbitrariness of a particular EoS for replicating observations. This leads us to comment on general properties EoS should obey to describe physically realistic stars. We also consider hydrostatic gas clouds immersed in larger regions having non-zero ambient density. We compare three analytical methods for finding solutions of these eigenvalue problems, including Taylor series solutions, the variational approximation, and the non-perturbative delta-expansion method. Although each method has benefits and drawbacks, we show that the delta-expansion method provides the most accuracy in replicating stellar structure.
Collisional excitation of methyl (iso)cyanide by He atoms: rate coefficients and isomerism effects
Authors: Ben Khalifa M , Dagdigian P J , Loreau J 
Published: May 2023

ABSTRACT
Among all closed-shell species observed in molecular clouds, molecules with C3v symmetry play a crucial role, as their rotational spectroscopy allows them to behave as a gas thermometer. In the interstellar medium, methyl cyanide (CH3CN) is the second most abundant of those (after ammonia, NH3). Its isomer, methyl isocyanide (CH3NC), is less abundant but has been detected in many astrophysical sources. In order to assess their absolute and relative abundances, it is essential to understand their collisional excitation properties. This paper reports the calculation of rate coefficients for rotational excitation of CH3CN and CH3NC molecules with He atoms, from low (5 K) to moderate (100 K) temperatures. We include the first 74 and 66 rotational states of both para and ortho symmetries of CH3CN and CH3NC, respectively. A propensity for Δj = 2 transitions is observed in the case of CH3CN-He collisions, whereas in the case of CH3NC-He a propensity for Δj = 1 is observed for transitions involving low values of j and at low temperatures, a propensity for Δj = 2 is observed for higher values of j and at high temperatures. A comparison of rate coefficients shows differences up to a factor of 3, depending on temperature and on the ortho/para symmetries for dominant transitions. This confirms the importance of having specific collisional data for each isomer. We also examined the effect of these new rates on the CH3CN and CH3NC excitation in molecular clouds by performing radiative transfer calculations of the excitation and brightness temperatures for several detected lines.
Harlem Stompers
Authors: Crease Stephanie Stein 
Published: May 2023

Abstract
In March 1928 Webb’s band, billed as Chick Webb and His Roseland Orchestra, made its debut at Harlem’s Lafayette Theater, considered “American’s Leading Colored Theater” from its opening in 1912 through the early 1930s. The Lafayette featured top Black entertainers, including Florence Mills, Ethel Waters, Bill Bojangles Robinson, Johnny Hutchins, and jazz bands. After Webb’s one-week run there he was back to hustling. In May 1928, Chick Webb and His Harlem Stompers returned to the Savoy Ballroom for another “Battle of Jazz.” There were important personnel changes in Webb’s band: Johnny Hodges joined Duke Ellington’s band after resisting Ellington’s offer for months. Another future Ellington star, trumpet player Cootie Williams, just arrived from Alabama and Webb heard him and hired him immediately. Though Webb struggled to find work, he inspired loyalty and was an excellent talent scout. Webb built a core ensemble eager to follow the latest jazz developments. Webb was often found arguing about music outside the Rhythm Club with Jelly Roll Morton, who’d recently moved to New York from Chicago. Webb enjoyed his status as a bandleader and held rehearsals every day whether his band had work or not. Webb got in trouble with Local 802 when he and his bandmates harassed another band working at the newly redecorated Alhambra Dance Hall.
Ol’ Man Depression
Authors: Crease Stephanie Stein 
Published: May 2023

Abstract
In October 1929, the Wall Street stock market crash initiated widespread economic depression. The entertainment world in Harlem was not immediately impacted but would be in the early 1930s. Webb interacted with Baltimore musicians who came to New York: Blanche Calloway, who was a star singer in Chicago clubs, and her then-unknown younger brother Cab. In 1930, Cab’s breakthrough performance in New York led to fronting the Missourians; they appeared with Webb’s band at the Savoy and other places. In 1931, the Cotton Club’s gangster owners hired Cab Calloway and the Missourians to succeed Duke Ellington’s band. Chick Webb and His Orchestra were busy through most of 1931 after a few weeks at the Roseland Ballroom. Webb, Henderson, and other Harlem bandleaders traded musicians or raided each other’s bands. In one instance, dubbed “The Big Trade,” alto saxophonist Benny Carter and trombonist Jimmy Harrison were “traded” to Webb’s band from Henderson’s for alto saxophonist Russell Procope and trombonist Benny Morton. On March 31, 1931, Webb’s band recorded three tunes, arranged by Benny Carter for Vocalion, all of which got good reviews. In October 1931, Webb’s band and Blanche Calloway’s band went on tour with Bennie Moten’s band and two others for a five-band roving “Battle of Music.” Chick Webb and His Orchestra were now frequently covered by the Black press.
Showtime in the Theater Wars
Authors: Crease Stephanie Stein 
Published: May 2023

Abstract
Since its opening in January 1934, the Apollo Theater was a hotspot for Black audiences and entertainers. Its biggest draw was the Wednesday Night Amateur contests, where Ella Fitzgerald won first prize in November 1934. This took place during the “Harlem Theater Wars” between Morris Sussman, the Apollo’s manager, and Frank Schiffman, manager of the Lafayette and the Harlem Opera House. The cutthroat competition ended in 1935 when Schiffman and Sussman agreed to co-run both houses. Webb benefited from the Theater Wars. His band had regular bookings at the Lafayette and Harlem Opera House and would become a big attraction at the Apollo. Webb’s career was now on a steady upswing thanks to his triweekly NBC national radio slots. In February 1935 Ella Fitzgerald appeared with Tiny Bradshaw’s band at the Harlem Opera House, her delayed “prize” for winning first place at the Apollo. Webb’s band members Bardu Ali, Charles Linton, and others encouraged Webb to hear her. He does, and then agreed to give her a tryout at a fraternity dance at Yale University during prom weekend. She went over so well that Webb hired her, and she started singing with the band at the Savoy. That winter Webb started dating a woman named Sally Hart (nee Martha Loretta Ferguson), and they started living together at an apartment on Striver’s Row in Harlem.
Vote for Mr. Rhythm
Authors: Crease Stephanie Stein 
Published: May 2023

Abstract
In early 1937, Ella Fitzgerald was getting acclaimed by entertainment reporters and the jazz press, Black and white; in November 1937 she was voted the Number One Female Vocalist in readers’ polls. Helen Oakley moved to New York to work for Duke Ellington’s manager, Irving Mills, who started two new record labels. She became producer for the Variety label, and asked Webb to be drummer for a few sessions. She did publicity work for Webb and his band in 1937–38. Band battles were still a big attraction at the Savoy Ballroom, where Webb’s band was almost always the winner. In February and March 1937 Webb’s band “battled” the orchestras of Henderson and Ellington, and Webb was “out-swung” by Ellington’s band. Oakley decided to stage a huge publicity event for Webb and set up a battle at the Savoy between Webb’s band and Benny Goodman’s. The Webb-Goodman “battle of the bands” was May 11, 1937, and took on legendary status almost immediately.
Have Mercy
Authors: Crease Stephanie Stein 
Published: May 2023

Abstract
In early June 1939, Webb and his band started on a big East Coast tour, with stops in Baltimore and Washington, DC. The band traveled with drummer Kaiser Marshall to sub for Webb if he needed to rest. On Monday, June 5, 1939, Chick Webb went back into Johns Hopkins Hospital, where he was treated by Dr. Young. Webb’s music director Teddy McRae caught up with the band back in DC, and they resumed their tour with stops in Virginia, the Carolinas, Georgia, and Alabama. This was the longest period Webb was absent, but his musicians thought he would recover, like he had before. Webb died at Johns Hopkins on June 16, 1939, of intestinal obstruction and uremia. Fitzgerald and the band had been on the road all day and were about to play for a dance in Montgomery, Alabama. During intermission, the hall’s manager told them that Chick Webb had just died. They played a few more numbers, then canceled the rest of the dance and boarded the bus to go back to Baltimore. Webb’s family in Baltimore prepared their home for the viewing of Webb’s body, and hundreds of people came to pay their respect. The funeral was held on June 20, 1939, at Waters AME Church. It was the biggest funeral the city had ever witnessed, and thousands of people thronged the streets surrounding the church and the cortege to Arbutus Memorial Park, where Webb was buried.
Write Like a Chemist
Authors: Robinson Marin S. , Stoller Fredricka L. 
Published: May 2023

Abstract
Write Like a Chemist (2nd ed.) is a one-of-a-kind volume, written to serve as a textbook and resource for chemistry students, post-docs, faculty, and other chemistry professionals. The book focuses on four types of chemistry writing: the journal article, conference abstract, scientific poster, and research proposal. The book includes numerous excerpts from American Chemical Society (ACS) journal articles, ACS conference abstracts, and successful NSF proposals, all serving as excellent models of scientific writing. A model poster is also included. Write Like a Chemist’s read–analyze–write approach underscores the importance of reading authentic texts, analyzing them, and using them as models for disciplinary writing. Analyses focus on conciseness, level of detail, and formality; organization; writing conventions; grammar and punctuation; and content expressed in prose and graphics. Exercises are included in each chapter. Together, these features turn the complex process of writing into graduated, achievable tasks. Additional features of the book include the formatting of figures, tables, citations, and references. ACS chemistry writing conventions, as advocated in the ACS Guide to Scholarly Communication (Banik et al., 2020), are modelled throughout. The final chapter provides language tips for “troublesome” aspects of writing. Separate companion websites include materials for students and faculty. For students, “writing on your own” guidance, a downloadable poster template, self-study exercises (with answer keys), and proofreading tips are included. For chemistry faculty, answer keys for book exercises, sample grading rubrics, and teaching tips are provided.
Learning to Write Like a Chemist
Authors: Robinson Marin S. , Stoller Fredricka L 
Published: May 2023

Abstract
This chapter provides an overview of the basic approach to writing in chemistry. It focuses on five components of genre analysis: audience and purpose, organization, writing conventions, grammar and punctuation, and science content. There are four genres commonly read and written by chemists: journal article; conference abstract; scientific poster; and research proposal. Before one begins to write, they must decide who will read their work (the audience) and why they are writing (the purpose). In turn, the audience and purpose will influence the levels of detail, formality, and conciseness that one uses in their writing and the words that they choose to use. The chapter then divides audience into four categories: expert audience, scientific audience, student audience, and general audience. Together, these four audiences form a continuum that spans a wide range of expertise in chemistry. The chapter also introduces move structures, which are flowchart-like representations of the moves within a genre.
Writing the Methods Section
Authors: Robinson Marin S. , Stoller Fredricka L 
Published: May 2023

Abstract
This chapter discusses the process of writing a Methods section for a journal-quality paper. The Methods section can vary significantly across different subdisciplines of chemistry: it is typically called Experimental or Methods in physical and analytical chemistry journals, Materials and Methods in environmental and biochemistry journals, and Experimental Section in organic and inorganic chemistry journals. The purpose of the Methods section is to explain how one’s research was conducted. Relevant information about instrumentation and experimental and/or numerical procedures is described. The goal is to provide enough detailed information so that an expert (not a novice) could repeat the work. Because journal-article Methods sections are written largely for experts, they are not at all like Methods sections in chemistry lab manuals. Concise writing is important because, unlike a single lab experiment, Methods sections in journal articles describe multifaceted works that took months or years to complete.
Writing the Introduction
Authors: Robinson Marin S. , Stoller Fredricka L 
Published: May 2023

Abstract
This chapter looks at the Introduction, the first major section of the journal article. The Introduction is often the first section to be read (by readers) but the last section to be written (by writers). This is because the Introduction must tell readers “where the article is going and why,” a mission that is most easily accomplished after the rest of the sections have been completed. The Introduction, as its name implies, sets the stage for the rest of the journal article by introducing the research area, describing its importance, and hinting at what new knowledge and insights the authors have gained. The Introduction is also where authors summarize others’ works, requiring several important writing skills such as paraphrasing, writing concisely, and correctly citing the literature. Like other journal-article sections, it follows a conventional organizational structure.
Figures and Tables
Authors: Robinson Marin S. , Stoller Fredricka L 
Published: May 2023

Abstract
This chapter provides general formatting guidelines for figures and tables (collectively referred to as graphics). Figures and tables, in combination with the text, allow authors to communicate information efficiently. Effective graphics help readers comprehend complex relationships between and among sets of data, relationships that would be difficult, if not impossible, to explain in words alone. Graphics also allow readers to view results independently, without being influenced by authors’ interpretations. The formatting guidelines presented in the chapter are general in nature and are designed to help authors prepare graphics appropriate for most chemistry genres. However, specific formatting requirements vary across genres; hence, authors will also need to consult appropriate resources for specifics. Author Guidelines for journal articles also specify if graphics should be attached to the end of the manuscript or inserted directly into the text.
Citations and References
Authors: Robinson Marin S. , Stoller Fredricka L 
Published: May 2023

Abstract
This chapter discusses formatting conventions for citations and references. It goes without saying that to include another’s original ideas without proper acknowledgment is plagiarism. Consequently, this stage of the writing process is critical both professionally and ethically. Citations—inserted into the text of journal articles, posters, and research proposals—identify publications that influenced the authors’ knowledge and understanding of the presented work. Although citations are formatted in different ways, they serve the same purposes, including acknowledging others’ works, enhancing the writer’s credibility, placing the current work into a broader context, and making it easy for readers to locate cited materials. Meanwhile, the purpose of references is to offer more detailed information about the publications cited within the text, making it easy for readers to retrieve each cited source, if so desired.