bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Algorithm to Calibrate and Correct the Response to Unpolarized Radiation of the X-Ray Polarimeter Onboard IXPE
Authors: Rankin John , Muleri Fabio , Tennant Allyn F. , Bachetti Matteo , Costa Enrico , Marco Alessandro Di , Fabiani Sergio , La Monaca Fabio , Soffitta Paolo , Tobia Antonino , Trois Alessio , Xie Fei , Baldini Luca , Di Lalla Niccolò , Manfreda Alberto , O’Dell Stephen L. , Perri Matteo , Puccetti Simonetta , Ramsey Brian D. , Sgrò Carmelo , Weisskopf Martin C. 
Published: January 2022

Abstract
The Gas Pixel Detector (GPD) is an X-ray polarimeter to fly onboard IXPE and other missions. To correctly measure the source polarization, the response of IXPE’s GPDs to unpolarized radiation has to be calibrated and corrected. In this paper, we describe the way such response is measured with laboratory sources and the algorithm to apply such correction to the observations of celestial sources. The latter allows to correct the response to polarization of single photons, therefore allowing great flexibility in all the subsequent analysis. Our correction approach is tested against both monochromatic and nonmonochromatic laboratory sources and with simulations, finding that it correctly retrieves the polarization up to the statistical limits of the planned IXPE observations.
Photometric Classification of Early-time Supernova Light Curves with SCONE
Authors: Qu Helen , Sako Masao 
Published: January 2022

Abstract
In this work, we present classification results on early supernova light curves from SCONE, a photometric classifier that uses convolutional neural networks to categorize supernovae (SNe) by type using light-curve data. SCONE is able to identify SN types from light curves at any stage, from the night of initial alert to the end of their lifetimes. Simulated LSST SNe light curves were truncated at 0, 5, 15, 25, and 50 days after the trigger date and used to train Gaussian processes in wavelength and time space to produce wavelength–time heatmaps. SCONE uses these heatmaps to perform six-way classification between SN types Ia, II, Ibc, Ia-91bg, Iax, and SLSN-I. SCONE is able to perform classification with or without redshift, but we show that incorporating redshift information improves performance at each epoch. SCONE achieved 75% overall accuracy at the date of trigger (60% without redshift), and 89% accuracy 50 days after trigger (82% without redshift). SCONE was also tested on bright subsets of SNe (r < 20 mag) and produced 91% accuracy at the date of trigger (83% without redshift) and 95% five days after trigger (94.7% without redshift). SCONE is the first application of convolutional neural networks to the early-time photometric transient classification problem. All of the data processing and model code developed for this paper can be found in the SCONE software package
1

1

github.com/helenqu/scone

located at github.com/helenqu/scone (Qu 2021).
Dynamical Mass of the Exoplanet Host Star HR 8799
Authors: Sepulveda Aldo G. , Bowler Brendan P. 
Published: January 2022

Abstract
HR 8799 is a young A5/F0 star hosting four directly imaged giant planets at wide separations (∼16–78 au), which are undergoing orbital motion and have been continuously monitored with adaptive optics imaging since their discovery over a decade ago. We present a dynamical mass of HR 8799 using 130 epochs of relative astrometry of its planets, which include both published measurements and new medium-band 3.1 μm observations that we acquired with NIRC2 at Keck Observatory. For the purpose of measuring the host-star mass, each orbiting planet is treated as a massless particle and is fit with a Keplerian orbit using Markov chain Monte Carlo. We then use a Bayesian framework to combine each independent total mass measurement into a cumulative dynamical mass using all four planets. The dynamical mass of HR 8799 is

1.47

−
0.17

+
0.12

M
⊙ assuming a uniform stellar mass prior, or

1.46

−
0.15

+
0.11

M
⊙ with a weakly informative prior based on spectroscopy. There is a strong covariance between the planets’ eccentricities and the total system mass; when the constraint is limited to low-eccentricity solutions of e < 0.1, which are motivated by dynamical stability, our mass measurement improves to

1.43

−
0.07

+
0.06

M
⊙. Our dynamical mass and other fundamental measured parameters of HR 8799 together with Modules for Experiments in Stellar Astrophysics Isochrones and Stellar Tracks grids yields a bulk metallicity most consistent with [Fe/H] ∼ −0.25–0.00 dex and an age of 10–23 Myr for the system. This implies hot-start masses of 2.7–4.9 M
Jup for HR 8799 b and 4.1–7.0 M
Jup for HR 8799 c, d, and e, assuming they formed at the same time as the host star.
The Transit Timing and Atmosphere of Hot Jupiter HAT-P-37b
Authors: A-thano Napaporn , Jiang Ing-Guey , Awiphan Supachai , Rattanamala Ronnakrit , Su Li-Hsin , Hengpiya Torik , Sariya Devesh P. , Yeh Li-Chin , Shlyapnikov A. A. , Gorbachev Mark A. , Rublevski Alexey N. , Mannaday Vineet Kumar , Thakur Parijat , Sahu D. K. , Mkrtichian David , Griv Evgeny 
Published: January 2022

Abstract
We perform transit timing variation (TTV) and transmission spectroscopy analyses of the planet HAT-P-37b, which is a hot Jupiter orbiting a G-type star. Nine new transit light curves are obtained and analyzed together with 21 published light curves from the literature. The updated physical parameters of HAT-P-37b are presented. The TTV analyses show a possibility that the system has an additional planet that induced the TTVs amplitude signal of 1.74 ± 0.17 minutes. If the body is located near the 1:2 mean-motion resonance orbit, the sinusoidal TTV signal could be caused by the gravitational interaction of a sub-Earth-mass planet with mass of 0.06 M
⊕. From the analysis of an upper-mass limit for the second planet, a Saturn-mass planet with orbital period less than 6 days is excluded. The broadband transmission spectra of HAT-P-37b favors a cloudy atmospheric model with an outlier spectrum in the B filter.
IM Normae: The Death Spiral of a Cataclysmic Variable?
Authors: Patterson Joseph , Kemp Jonathan , Monard Berto , Myers Gordon , de Miguel Enrique , Hambsch Franz-Josef , Warhurst Paul , Rea Robert , Dvorak Shawn , Menzies Kenneth , Vanmunster Tonny , Roberts George , Campbell Tut , Starkey Donn , Ulowetz Joseph , Rock John , Seargeant Jim , Boardman James , Lemay Damien , Cejudo David , Knigge Christian 
Published: January 2022

Abstract
We present a study of the orbital light curves of the recurrent nova IM Normae since its 2002 outburst. The broad “eclipses” recur with a 2.46 hr period, which increases on a timescale of 1.28(16) × 106 yr. Under the assumption of conservative mass transfer, this suggests a rate near 10−7
M
⊙ yr−1, and this agrees with the estimated accretion rate of the postnova, based on our estimate of luminosity. IM Nor appears to be a close match to the famous recurrent nova T Pyxidis. Both stars appear to have very high accretion rates, sufficient to drive the recurrent-nova events. Both have quiescent light curves, which suggest strong heating of the low-mass secondary, and very wide orbital minima, which suggest obscuration of a large “corona” around the primary. And both have very rapid orbital period increases, as expected from a short-period binary with high mass transfer from the low-mass component. These two stars may represent a final stage of nova—and cataclysmic variable—evolution, in which irradiation-driven winds drive a high rate of mass transfer, thereby evaporating the donor star in a paroxysm of nova outbursts.
Searching for Gravitationally Lensed Gamma-Ray Bursts with Their Afterglows
Authors: Chen Shengnan , Wen Xudong , Gao He , Liao Kai , Liu Liangduan , Zhao Litao , Li Zhengxiang , Biesiada Marek , Piórkowska-Kurpas Aleksandra , Xiao Shuo , Xiong Shaolin 
Published: January 2022

Abstract
Gamma-ray bursts (GRBs) at high redshifts are expected to be gravitationally lensed by objects of different mass scales. Other than a single recent claim, no lensed GRB has been detected so far by using gamma-ray data only. In this paper, we suggest that multiband afterglow data might be an efficient way to search for lensed GRB events. Using the standard afterglow model, we calculate the characteristics of the lensed afterglow lightcurves under the assumption of two popular analytic lens models: the point-mass and singular isothermal sphere models. In particular, when different lensed images cannot be resolved, their signals would be superimposed together with a given time delay. In this case, the X-ray afterglows are likely to contain several X-ray flares of similar width in linear scale and similar spectrum, and the optical afterglow lightcurve will show re-brightening signatures. Since the lightcurves from the image arriving later would be compressed and deformed in the logarithmic timescale, the larger time delay (i.e., the larger mass of the lens), the easier it is to identify the lensing effect. We analyzed the archival data of optical afterglows and found one potential candidate of the lensed GRB (130831A) with time delay ∼500 s; however, observations of this event in gamma-ray and X-ray bands seem not to support the lensing hypothesis. In the future, with the cooperation of the all-sky monitoring gamma-ray detectors and multiband sky survey projects, the method proposed in this paper would be more efficient in searching for strongly lensed GRBs.
Galactic Chemical Evolution of Radioactive Isotopes with an s-process Contribution
Authors: Trueman Thomas C. L. , Côté Benoit , Yagüe López Andrés , den Hartogh Jacqueline , Pignatari Marco , Soós Benjámin , Karakas Amanda I. , Lugaro Maria 
Published: January 2022

Abstract
Analysis of inclusions in primitive meteorites reveals that several short-lived radionuclides (SLRs) with half-lives of 0.1–100 Myr existed in the early solar system (ESS). We investigate the ESS origin of 107Pd, 135Cs, and 182Hf, which are produced by slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. We modeled the Galactic abundances of these SLRs using the OMEGA+ galactic chemical evolution (GCE) code and two sets of mass- and metallicity-dependent AGB nucleosynthesis yields (Monash and FRUITY). Depending on the ratio of the mean-life τ of the SLR to the average length of time between the formations of AGB progenitors γ, we calculate timescales relevant for the birth of the Sun. If τ/γ ≳ 2, we predict self-consistent isolation times between 9 and 26 Myr by decaying the GCE predicted 107Pd/108Pd, 135Cs/133Cs, and 182Hf/180Hf ratios to their respective ESS ratios. The predicted 107Pd/182Hf ratio indicates that our GCE models are missing 9%–73% of 107Pd and 108Pd in the ESS. This missing component may have come from AGB stars of higher metallicity than those that contributed to the ESS in our GCE code. If τ/γ ≲ 0.3, we calculate instead the time (T
LE) from the last nucleosynthesis event that added the SLRs into the presolar matter to the formation of the oldest solids in the ESS. For the 2 M
⊙, Z = 0.01 Monash model we find a self-consistent solution of T
LE = 25.5 Myr.
Photodynamical Modeling of the Fascinating Eclipses in the Triple-star System KOI-126
Authors: Yenawine Mitchell E. , Welsh William F. , Orosz Jerome A. , Bieryla Allyson , Cochran William D. , Endl Michael , Latham David W. , Quinn Samuel N. , Short Donald R. , Windmiller Gur 
Published: January 2022

Abstract
We explore the fascinating eclipses and dynamics of the compact hierarchical triple-star system KOI-126 (KIC 5897826). This system is composed of a pair of M-dwarf stars (KOI-126 B and C) in a 1.74 day orbit that revolve around an F star (KOI-126 A) every 34 days. Complex eclipse shapes are created as the M stars transit the F star, due to two effects: (1) the duration of the eclipse is a significant fraction of the M-star orbital period, so the prograde or retrograde motion of the M stars in their orbit lead to unusually short or long duration eclipses; (2) due to 3-body dynamics, the M-star orbit precesses with an astonishingly quick timescale of 1.74 yr for the periastron (apsidal) precession, and 2.73 yr for the inclination and nodal angle precession. Using the full Kepler data set, supplemented with ground-based photometry, plus 29 radial velocity measurements that span 6 yr, our photodynamical modeling yields masses of M

A
= 1.2713 ± 0.0047 M
⊙ (0.37%), M

B
= 0.23529 ± 0.00062 M
⊙ (0.26%), and M

C
= 0.20739 ± 0.00055 M
⊙ (0.27%) and radii of R

A
= 1.9984 ± 0.0027 R
⊙ (0.14%), R

B
= 0.25504 ± 0.00076 R
⊙ (0.3%), and R

C
= 0.23196 ± 0.00069 R
⊙ (0.3%). We also estimate the apsidal motion constant of the M dwarfs, a parameter that characterizes the internal mass distribution. Although it is not particularly precise, we measure a mean apsidal motion constant,

k

2

¯

, of

0.046

−
0.028

+
0.046

, which is approximately 2σ lower than the theoretical model prediction of 0.150. We explore possible causes for this discrepancy.
CH3-Terminated Carbon Chains in the GOTHAM Survey of TMC-1: Evidence of Interstellar CH3C7N
Authors: Siebert Mark A. , Lee Kin Long Kelvin , Remijan Anthony J. , Burkhardt Andrew M. ,   The GOTHAM Collaboration, Loomis Ryan A. , McCarthy Michael C. , McGuire Brett A. 
Published: January 2022

Abstract
We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov Chain Monte Carlo simulations and spectral line stacking of over 30 rotational transitions, we report statistically significant emission from methylcyanotriacetylene (CH3C7N) at a confidence level of 4.6σ, and use it to derive a column density of ∼1011 cm−2. We also searched for the related species, methyltetraacetylene (CH3C8H), and place upper limits on the column density of this molecule. By carrying out the above statistical analyses for all other previously detected methyl-terminated carbon chains that have emission lines in our survey, we assess the abundances, excitation conditions, and formation chemistry of methylpolyynes (CH3C2n
H) and methylcyanopolyynes (CH3C2n-1N) in TMC-1, and compare those with predictions from a chemical model. Based on our observed trends in column density and relative populations of the A and E nuclear spin isomers, we find that the methylpolyyne and methylcyanopolyyne families exhibit stark differences from one another, pointing to separate interstellar formation pathways, which is confirmed through gas–grain chemical modeling with nautilus.
The Eccentric Nature of Eccentric Tidal Disruption Events
Authors: Cufari M. , Coughlin Eric R. , Nixon C. J. 
Published: January 2022

Abstract
Upon entering the tidal sphere of a supermassive black hole, a star is ripped apart by tides and transformed into a stream of debris. The ultimate fate of that debris, and the properties of the bright flare that is produced and observed, depends on a number of parameters, including the energy of the center of mass of the original star. Here we present the results of a set of smoothed particle hydrodynamics simulations in which a 1M
⊙, γ = 5/3 polytrope is disrupted by a 106
M
⊙ supermassive black hole. Each simulation has a pericenter distance of r
p = r
t (i.e., β ≡ r
t/r
p = 1 with r
t the tidal radius), and we vary the eccentricity e of the stellar orbit from e = 0.8 up to e = 1.20 and study the nature of the fallback of debris onto the black hole and the long-term fate of the unbound material. For simulations with eccentricities e ≲ 0.98, the fallback curve has a distinct, three-peak structure that is induced by self-gravity. For simulations with eccentricities e ≳ 1.06, the core of the disrupted star reforms following its initial disruption. Our results have implications for, e.g., tidal disruption events produced by supermassive black hole binaries.
Simultaneous High Dynamic Range Algorithm, Testing, and Instrument Simulation
Authors: Mason James Paul , Seaton Daniel B. , Jones Andrew R. , Jin Meng , Chamberlin Phillip C. , Sims Alan , Woods Thomas N. 
Published: January 2022

Abstract
Within an imaging instrument’s field of view, there may be many observational targets of interest. Similarly, within a spectrograph’s bandpass, there may be many emission lines of interest. The brightness of these targets and lines can be orders of magnitude different, which poses a challenge to instrument and mission design. A single exposure can saturate the bright emission and/or have a low signal-to-noise ratio (S/N) for faint emission. Traditional high dynamic range (HDR) techniques solve this problem by either combining multiple sequential exposures of varied duration or splitting the light to different sensors. These methods, however, can result in the loss of science capability, reduced observational efficiency, or increased complexity and cost. The simultaneous HDR method described in this paper avoids these issues by utilizing a special type of detector whose rows can be read independently to define zones that are then composited, resulting in areas with short or long exposure measured simultaneously. We demonstrate this technique for the Sun, which is bright on disk and faint off disk. We emulated these conditions in the lab to validate the method. We built an instrument simulator to demonstrate the method for a realistic solar imager and input. We then calculated S/Ns, finding a value of 45 for a faint coronal mass ejection and 200 for a bright one, both at 3.5



⊙

N

—meeting or far exceeding the international standard for digital photography that defines an S/N of 10 as acceptable and 40 as excellent. Future missions should consider this type of hardware and technique in their trade studies for instrument design.
Spatially Resolved Stellar Spectroscopy of the Ultra-diffuse Galaxy Dragonfly 44. III. Evidence for an Unexpected Star Formation History under Conventional Galaxy Evolution Processes
Authors: Villaume Alexa , Romanowsky Aaron J. , Brodie Jean , van Dokkum Pieter , Conroy Charlie , Forbes Duncan A. , Danieli Shany , Martin Christopher , Matuszewski Matt 
Published: January 2022

Abstract
We use the Keck Cosmic Web Imager integral field unit spectrograph to (1) measure the global stellar population parameters for the ultra-diffuse galaxy (UDG) Dragonfly 44 (DF44) to much higher precision than previously possible for any UDG and (2) for the first time measure spatially resolved stellar population parameters of a UDG. We find that DF44 falls below the mass–metallicity relation established by canonical dwarf galaxies both in and beyond the Local Group. We measure a flat radial age gradient (

m

logage

=
+

0.01

−
0.08

+
0.08

log Gyr kpc−1) and a flat to positive metallicity gradient (

m

[
Fe

/

H
]

=
+

0.09

−
0.12

+
0.11

dex kpc−1), which are inconsistent with the gradients measured in similarly pressure-supported dwarf galaxies. We also measure a negative [Mg/Fe] gradient (

m

[
Mg

/

Fe
]

=
−

0.20

−
0.18

+
0.18

) dex kpc−1 such that the central 1.5 kpc of DF44 has stellar population parameters comparable to metal-poor globular clusters. Overall, DF44 does not have internal properties similar to other dwarf galaxies and is inconsistent with it having been puffed up through a prolonged, bursty star formation history, as suggested by some simulations. Rather, the evidence indicates that DF44 experienced an intense epoch of “inside-out” star formation and then quenched early and catastrophically, such that star formation was cut off more quickly than in canonical dwarf galaxies.
Tracing Birth Properties of Stars with Abundance Clustering
Authors: Ratcliffe Bridget L. , Ness Melissa K. , Buck Tobias , Johnston Kathryn V. , Sen Bodhisattva , Beraldo e Silva Leandro , Debattista Victor P. 
Published: January 2022

Abstract
To understand the formation and evolution of the Milky Way disk, we must connect its current properties to its past. We explore hydrodynamical cosmological simulations to investigate how the chemical abundances of stars might be linked to their origins. Using hierarchical clustering of abundance measurements in two Milky Way–like simulations with distributed and steady star formation histories, we find that groups of chemically similar stars comprise different groups in birth place (R
birth) and time (age). Simulating observational abundance errors (0.05 dex), we find that to trace distinct groups of (R
birth, age) requires a large vector of abundances. Using 15 element abundances (Fe, O, Mg, S, Si, C, P, Mn, Ne, Al, N, V, Ba, Cr, Co), up to ≈10 groups can be defined with ≈25% overlap in (R
birth, age). We build a simple model to show that in the context of these simulations, it is possible to infer a star’s age and R
birth from abundances with precisions of ±0.06 Gyr and ±1.17 kpc, respectively. We find that abundance clustering is ineffective for a third simulation, where low-α stars form distributed in the disk and early high-α stars form more rapidly in clumps that sink toward the Galactic center as their constituent stars evolve to enrich the interstellar medium. However, this formation path leads to large age dispersions across the [α/Fe]–[Fe/H] plane, which is inconsistent with the Milky Way’s observed properties. We conclude that abundance clustering is a promising approach toward charting the history of our Galaxy.
Spectral Analysis of Solar Radio Type III Bursts from 20 kHz to 410 MHz
Authors: Sasikumar Raja K. , Maksimovic Milan , Kontar Eduard P. , Bonnin Xavier , Zarka Philippe , Lamy Laurent , Reid Hamish , Vilmer Nicole , Lecacheux Alain , Krupar Vratislav , Cecconi Baptiste , Nora Lahmiti , Denis Laurent 
Published: January 2022

Abstract
We present the statistical analysis of the spectral response of solar radio type III bursts over the wide frequency range between 20 kHz and 410 MHz. For this purpose, we have used observations that were carried out using both spaced-based (Wind/Waves) and ground-based (Nançay Decameter Array and Nançay Radioheliograph) facilities. In order to compare the flux densities observed by the different instruments, we have carefully calibrated the data and displayed them in solar flux units. The main result of our study is that type III bursts, in the metric to hectometric wavelength range, statistically exhibit a clear maximum of their median radio flux density around 2 MHz. Although this result was already reported by inspecting the spectral profiles of type III bursts in the frequency range 20 kHz–20 MHz, our study extends such analysis for the first time to metric radio frequencies (i.e., from 20 kHz to 410 MHz) and confirms the maximum spectral response around 2 MHz. In addition, using a simple empirical model we show that the median radio flux S of the studied data set obeys the polynomial form Y = 0.04X
3 − 1.63X
2 + 16.30X − 41.24, with

X
=
ln
(

F

MHz

)

and with

Y
=
ln
(

S

SFU

)

. Using the Sittler and Guhathakurtha model for coronal streamers, we have found that the maximum of radio power therefore falls in the range 4 to 10 R
⊙, depending on whether the type III emissions are assumed to be at the fundamental or the harmonic.
Impact of Hypernova νp-process Nucleosynthesis on the Galactic Chemical Evolution of Mo and Ru
Authors: Sasaki Hirokazu , Yamazaki Yuta , Kajino Toshitaka , Kusakabe Motohiko , Hayakawa Takehito , Cheoun Myung-Ki , Ko Heamin , Mathews Grant J. 
Published: January 2022

Abstract
We calculate the Galactic Chemical Evolution of Mo and Ru by taking into account the contribution from ν
p-process nucleosynthesis. We estimate yields of p-nuclei such as 92,94Mo and 96,98Ru through the ν
p-process in various supernova progenitors based upon recent models. In particular, the ν
p-process in energetic hypernovae produces a large amount of p-nuclei compared to the yield in ordinary core-collapse SNe. Because of this, the abundances of 92,94Mo and 96,98Ru in the Galaxy are significantly enhanced at [Fe/H] = 0 by the ν
p-process. We find that the ν
p-process in hypernovae is the main contributor to the elemental abundance of 92Mo at low metallicity [Fe/H] < −2. Our theoretical prediction of the elemental abundances in metal-poor stars becomes more consistent with observational data when the ν
p-process in hypernovae is taken into account.