@misc{14995,
abstract = {Lincheck is a new practical and user-friendly framework for testing concurrent data structures on the Java Virtual Machine (JVM). It provides a simple and declarative way to write concurrent tests. Instead of describing how to perform the test, users specify what to test by declaring all the operations to examine; the framework automatically handles the rest. As a result, tests written with Lincheck are concise and easy to understand.
The artifact presents a collection of Lincheck tests that discover new bugs in popular libraries and implementations from the concurrency literature -- they are listed in Table 1, Section 3. To evaluate the performance of Lincheck analysis, the collection of tests also includes those which check correct data structures and, thus, always succeed. Similarly to Table 2, Section 3, the experiments demonstrate the reasonable time to perform a test. Finally, Lincheck provides user-friendly output with an easy-to-follow trace to reproduce a detected error, significantly simplifying further investigation.},
author = {Koval, Nikita and Fedorov, Alexander and Sokolova, Maria and Tsitelov, Dmitry and Alistarh, Dan-Adrian},
publisher = {Zenodo},
title = {{Lincheck: A practical framework for testing concurrent data structures on JVM}},
doi = {10.5281/ZENODO.7877757},
year = {2023},
}
@inproceedings{15023,
abstract = {Reinforcement learning has shown promising results in learning neural network policies for complicated control tasks. However, the lack of formal guarantees about the behavior of such policies remains an impediment to their deployment. We propose a novel method for learning a composition of neural network policies in stochastic environments, along with a formal certificate which guarantees that a specification over the policy's behavior is satisfied with the desired probability. Unlike prior work on verifiable RL, our approach leverages the compositional nature of logical specifications provided in SpectRL, to learn over graphs of probabilistic reach-avoid specifications. The formal guarantees are provided by learning neural network policies together with reach-avoid supermartingales (RASM) for the graph’s sub-tasks and then composing them into a global policy. We also derive a tighter lower bound compared to previous work on the probability of reach-avoidance implied by a RASM, which is required to find a compositional policy with an acceptable probabilistic threshold for complex tasks with multiple edge policies. We implement a prototype of our approach and evaluate it on a Stochastic Nine Rooms environment.},
author = {Zikelic, Dorde and Lechner, Mathias and Verma, Abhinav and Chatterjee, Krishnendu and Henzinger, Thomas A},
booktitle = {37th Conference on Neural Information Processing Systems},
location = {New Orleans, LO, United States},
title = {{Compositional policy learning in stochastic control systems with formal guarantees}},
year = {2023},
}
@misc{15027,
abstract = {This data repository underpins the paper, published in PNAS (doi pending) and bioarxiv (doi: https://doi.org/10.1101/2023.07.05.547777).},
author = {Curk, Samo},
publisher = {Figshare},
title = {{aggregation_data}},
year = {2023},
}
@misc{15035,
abstract = {This artifact aims to reproduce experiments from the paper Monitoring Hyperproperties With Prefix Transducers accepted at RV'23, and give further pointers to implementation of prefix transducers.
It has two parts: a pre-compiled docker image and sources that one can use to compile (locally or in docker) the software and run the experiments.},
author = {Chalupa, Marek and Henzinger, Thomas A},
publisher = {Zenodo},
title = {{Monitoring hyperproperties with prefix transducers}},
doi = {10.5281/ZENODO.8191723},
year = {2023},
}
@article{15085,
abstract = {The hydrogen-rich outer layers of massive stars can be removed by interactions with a binary companion. Theoretical models predict that this stripping produces a population of hot helium stars of ~2 to 8 solar masses (M☉), however, only one such system has been identified thus far. We used ultraviolet photometry to identify potential stripped helium stars then investigated 25 of them using optical spectroscopy. We identified stars with high temperatures (~60,000 to 100,000 kelvin), high surface gravities, and hydrogen-depleted surfaces; 16 stars also showed binary motion. These properties match expectations for stars with initial masses of 8 to 25 M☉ that were stripped by binary interaction. Their masses fall in the gap between subdwarf helium stars and Wolf-Rayet stars. We propose that these stars could be progenitors of stripped-envelope supernovae.},
author = {Drout, M. R. and Götberg, Ylva Louise Linsdotter and Ludwig, B. A. and Groh, J. H. and de Mink, S. E. and O’Grady, A. J. G. and Smith, N.},
issn = {1095-9203},
journal = {Science},
keywords = {Stellar Astrophysics},
number = {6676},
pages = {1287--1291},
publisher = {American Association for the Advancement of Science},
title = {{An observed population of intermediate-mass helium stars that have been stripped in binaries}},
doi = {10.1126/science.ade4970},
volume = {382},
year = {2023},
}
@article{15129,
abstract = {Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various stages of double-stranded (ds)DNA target capture, revealing mechanisms that underpin PAM recognition and Cascade allosteric activation. We uncover an interesting mechanism of non-target strand (NTS) DNA stabilization via stacking interactions with the “belly” subunits, securing the NTS in place. This “molecular seatbelt” mechanism facilitates efficient R-loop formation and prevents dsDNA reannealing. Additionally, we provide structural insights into how two anti-CRISPR (Acr) proteins utilize distinct strategies to achieve a shared mechanism of type I-C Cascade inhibition by blocking PAM scanning. These observations form a structural basis for directional R-loop formation and reveal how different Acr proteins have converged upon common molecular mechanisms to efficiently shut down CRISPR immunity.},
author = {O’Brien, Roisin E. and Bravo, Jack Peter Kelly and Ramos, Delisa and Hibshman, Grace N. and Wright, Jacquelyn T. and Taylor, David W.},
issn = {1097-2765},
journal = {Molecular Cell},
keywords = {Cell Biology, Molecular Biology},
number = {5},
pages = {746--758.e5},
publisher = {Elsevier},
title = {{Structural snapshots of R-loop formation by a type I-C CRISPR Cascade}},
doi = {10.1016/j.molcel.2023.01.024},
volume = {83},
year = {2023},
}
@article{15130,
abstract = {Cas12a2 is a CRISPR-associated nuclease that performs RNA-guided, sequence-nonspecific degradation of single-stranded RNA, single-stranded DNA and double-stranded DNA following recognition of a complementary RNA target, culminating in abortive infection1. Here we report structures of Cas12a2 in binary, ternary and quaternary complexes to reveal a complete activation pathway. Our structures reveal that Cas12a2 is autoinhibited until binding a cognate RNA target, which exposes the RuvC active site within a large, positively charged cleft. Double-stranded DNA substrates are captured through duplex distortion and local melting, stabilized by pairs of ‘aromatic clamp’ residues that are crucial for double-stranded DNA degradation and in vivo immune system function. Our work provides a structural basis for this mechanism of abortive infection to achieve population-level immunity, which can be leveraged to create rational mutants that degrade a spectrum of collateral substrates.},
author = {Bravo, Jack Peter Kelly and Hallmark, Thomson and Naegle, Bronson and Beisel, Chase L. and Jackson, Ryan N. and Taylor, David W.},
issn = {1476-4687},
journal = {Nature},
number = {7944},
pages = {582--587},
publisher = {Springer Nature},
title = {{RNA targeting unleashes indiscriminate nuclease activity of CRISPR–Cas12a2}},
doi = {10.1038/s41586-022-05560-w},
volume = {613},
year = {2023},
}
@article{15148,
abstract = {The basic helix–loop–helix (bHLH) family of transcription factors recognizes DNA motifs known as E-boxes (CANNTG) and includes 108 members1. Here we investigate how chromatinized E-boxes are engaged by two structurally diverse bHLH proteins: the proto-oncogene MYC-MAX and the circadian transcription factor CLOCK-BMAL1 (refs. 2,3). Both transcription factors bind to E-boxes preferentially near the nucleosomal entry–exit sites. Structural studies with engineered or native nucleosome sequences show that MYC-MAX or CLOCK-BMAL1 triggers the release of DNA from histones to gain access. Atop the H2A–H2B acidic patch4, the CLOCK-BMAL1 Per-Arnt-Sim (PAS) dimerization domains engage the histone octamer disc. Binding of tandem E-boxes5–7 at endogenous DNA sequences occurs through direct interactions between two CLOCK-BMAL1 protomers and histones and is important for circadian cycling. At internal E-boxes, the MYC-MAX leucine zipper can also interact with histones H2B and H3, and its binding is indirectly enhanced by OCT4 elsewhere on the nucleosome. The nucleosomal E-box position and the type of bHLH dimerization domain jointly determine the histone contact, the affinity and the degree of competition and cooperativity with other nucleosome-bound factors.},
author = {Michael, Alicia and Stoos, Lisa and Crosby, Priya and Eggers, Nikolas and Nie, Xinyu Y. and Makasheva, Kristina and Minnich, Martina and Healy, Kelly L. and Weiss, Joscha and Kempf, Georg and Cavadini, Simone and Kater, Lukas and Seebacher, Jan and Vecchia, Luca and Chakraborty, Deyasini and Isbel, Luke and Grand, Ralph S. and Andersch, Florian and Fribourgh, Jennifer L. and Schübeler, Dirk and Zuber, Johannes and Liu, Andrew C. and Becker, Peter B. and Fierz, Beat and Partch, Carrie L. and Menet, Jerome S. and Thomä, Nicolas H.},
issn = {1476-4687},
journal = {Nature},
number = {7969},
pages = {385--393},
publisher = {Springer Nature},
title = {{Cooperation between bHLH transcription factors and histones for DNA access}},
doi = {10.1038/s41586-023-06282-3},
volume = {619},
year = {2023},
}
@article{15149,
abstract = {The genomic binding sites of the transcription factor (TF) and tumor suppressor p53 are unusually diverse with regard to their chromatin features, including histone modifications, raising the possibility that the local chromatin environment can contextualize p53 regulation. Here, we show that epigenetic characteristics of closed chromatin, such as DNA methylation, do not influence the binding of p53 across the genome. Instead, the ability of p53 to open chromatin and activate its target genes is locally restricted by its cofactor Trim24. Trim24 binds to both p53 and unmethylated histone 3 lysine 4 (H3K4), thereby preferentially localizing to those p53 sites that reside in closed chromatin, whereas it is deterred from accessible chromatin by H3K4 methylation. The presence of Trim24 increases cell viability upon stress and enables p53 to affect gene expression as a function of the local chromatin state. These findings link H3K4 methylation to p53 function and illustrate how specificity in chromatin can be achieved, not by TF-intrinsic sensitivity to histone modifications, but by employing chromatin-sensitive cofactors that locally modulate TF function.},
author = {Isbel, Luke and Iskar, Murat and Durdu, Sevi and Weiss, Joscha and Grand, Ralph S. and Hietter-Pfeiffer, Eric and Kozicka, Zuzanna and Michael, Alicia and Burger, Lukas and Thomä, Nicolas H. and Schübeler, Dirk},
issn = {1545-9985},
journal = {Nature Structural & Molecular Biology},
keywords = {Molecular Biology, Structural Biology},
number = {7},
pages = {948--957},
publisher = {Springer Nature},
title = {{Readout of histone methylation by Trim24 locally restricts chromatin opening by p53}},
doi = {10.1038/s41594-023-01021-8},
volume = {30},
year = {2023},
}
@article{15173,
abstract = {We show that the number of linear spaces on a set of n points and the number of rank-3 matroids on a ground set of size n are both of the form (cn+o(n))n2/6, where c=e3√/2−3(1+3–√)/2. This is the final piece of the puzzle for enumerating fixed-rank matroids at this level of accuracy: the numbers of rank-1 and rank-2 matroids on a ground set of size n have exact representations in terms of well-known combinatorial functions, and it was recently proved by van der Hofstad, Pendavingh, and van der Pol that for constant r≥4 there are (e1−rn+o(n))nr−1/r! rank-r matroids on a ground set of size n. In our proof, we introduce a new approach for bounding the number of clique decompositions of a complete graph, using quasirandomness instead of the so-called entropy method that is common in this area.},
author = {Kwan, Matthew Alan and Sah, Ashwin and Sawhney, Mehtaab},
issn = {1778-3569},
journal = {Comptes Rendus Mathematique},
number = {G2},
pages = {565--575},
publisher = {Academie des Sciences},
title = {{Enumerating matroids and linear spaces}},
doi = {10.5802/crmath.423},
volume = {361},
year = {2023},
}
@article{15190,
abstract = {We report on IXPE, NICER, and XMM–Newton observations of the magnetar 1E 2259+586. We find that the source is significantly polarized at about or above 20 per cent for all phases except for the secondary peak where it is more weakly polarized. The polarization degree is strongest during the primary minimum which is also the phase where an absorption feature has been identified previously. The polarization angle of the photons are consistent with a rotating vector model with a mode switch between the primary minimum and the rest of the rotation of the neutron star. We propose a scenario in which the emission at the source is weakly polarized (as in a condensed surface) and, as the radiation passes through a plasma arch, resonant cyclotron scattering off of protons produces the observed polarized radiation. This confirms the magnetar nature of the source with a surface field greater than about 1015 G.},
author = {Heyl, Jeremy and Taverna, Roberto and Turolla, Roberto and Israel, Gian Luca and Ng, Mason and Kırmızıbayrak, Demet and González-Caniulef, Denis and Caiazzo, Ilaria and Zane, Silvia and Ehlert, Steven R and Negro, Michela and Agudo, Iván and Antonelli, Lucio Angelo and Bachetti, Matteo and Baldini, Luca and Baumgartner, Wayne H and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Cavazzuti, Elisabetta and Chen, Chien-Ting and Ciprini, Stefano and Costa, Enrico and De Rosa, Alessandra and Del Monte, Ettore and Di Gesu, Laura and Di Lalla, Niccolò and Di Marco, Alessandro and Donnarumma, Immacolata and Doroshenko, Victor and Dovčiak, Michal and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and Garcia, Javier A and Gunji, Shuichi and Hayashida, Kiyoshi and Iwakiri, Wataru and Jorstad, Svetlana G and Kaaret, Philip and Karas, Vladimir and Kislat, Fabian and Kitaguchi, Takao and Kolodziejczak, Jeffery J and Krawczynski, Henric and Monaca, Fabio La and Latronico, Luca and Liodakis, Ioannis and Maldera, Simone and Manfreda, Alberto and Marin, Frédéric and Marinucci, Andrea and Marscher, Alan P and Marshall, Herman L and Massaro, Francesco and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Muleri, Fabio and Ng, C-Y and O’Dell, Stephen L and Omodei, Nicola and Oppedisano, Chiara and Papitto, Alessandro and Pavlov, George G and Peirson, Abel Lawrence and Perri, Matteo and Pesce-Rollins, Melissa and Petrucci, Pierre-Olivier and Pilia, Maura and Possenti, Andrea and Poutanen, Juri and Puccetti, Simonetta and Ramsey, Brian D and Rankin, John and Ratheesh, Ajay and Roberts, Oliver J and Romani, Roger W and Sgrò, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria and Swartz, Douglas A and Tamagawa, Toru and Tavecchio, Fabrizio and Tawara, Yuzuru and Tennant, Allyn F and Thomas, Nicholas E and Tombesi, Francesco and Trois, Alessio and Tsygankov, Sergey S and Vink, Jacco and Weisskopf, Martin C and Wu, Kinwah and Xie, Fei},
issn = {1365-2966},
journal = {Monthly Notices of the Royal Astronomical Society},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {4},
pages = {12219--12231},
publisher = {Oxford University Press},
title = {{The detection of polarized X-ray emission from the magnetar 1E 2259+586}},
doi = {10.1093/mnras/stad3680},
volume = {527},
year = {2023},
}
@article{15192,
abstract = {We searched the Gaia DR3 database for ultramassive white dwarfs with kinematics consistent with having escaped the nearby Hyades open cluster, identifying three such candidates. Two of these candidates have masses estimated from Gaia photometry of approximately 1.1 solar masses; their status as products of single-stellar evolution that have escaped the cluster was deemed too questionable for immediate follow-up analysis. The remaining candidate has an expected mass >1.3 solar masses, significantly reducing the probability of it being an interloper. Analysis of follow-up Gemini GMOS spectroscopy for this source reveals a nonmagnetized hydrogen atmosphere white dwarf with a mass and age consistent with having formed from a single star. Assuming a single-stellar-evolution formation channel, we estimate a 97.8% chance that the candidate is a true escapee from the Hyades. With a determined mass of 1.317 solar masses, this is potentially the most massive known single-evolution white dwarf and is by far the most massive with a strong association with an open cluster.},
author = {Miller, David R. and Caiazzo, Ilaria and Heyl, Jeremy and Richer, Harvey B. and El-Badry, Kareem and Rodriguez, Antonio C. and Vanderbosch, Zachary P. and van Roestel, Jan},
issn = {2041-8213},
journal = {The Astrophysical Journal Letters},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {2},
publisher = {American Astronomical Society},
title = {{An extremely massive white dwarf escaped from the Hyades star cluster}},
doi = {10.3847/2041-8213/acffc4},
volume = {956},
year = {2023},
}
@article{15193,
abstract = {We report on Imaging X-ray polarimetry explorer (IXPE) observations of the Be-transient X-ray pulsar LS V +44 17/RX J0440.9+4431 made at two luminosity levels during the giant outburst in January–February 2023. Considering the observed spectral variability and changes in the pulse profiles, the source was likely caught in supercritical and subcritical states with significantly different emission-region geometry, associated with the presence of accretion columns and hot spots, respectively. We focus here on the pulse-phase-resolved polarimetric analysis and find that the observed dependencies of the polarization degree and polarization angle (PA) on the pulse phase are indeed drastically different for the two observations. The observed differences, if interpreted within the framework of the rotating vector model (RVM), imply dramatic variations in the spin axis inclination, the position angle, and the magnetic colatitude by tens of degrees within the space of just a few days. We suggest that the apparent changes in the observed PA phase dependence are predominantly related to the presence of an unpulsed polarized component in addition to the polarized radiation associated with the pulsar itself. We then show that the observed PA phase dependence in both observations can be explained with a single set of RVM parameters defining the pulsar’s geometry. We also suggest that the additional polarized component is likely produced by scattering of the pulsar radiation in the equatorial disk wind.},
author = {Doroshenko, Victor and Poutanen, Juri and Heyl, Jeremy and Tsygankov, Sergey S. and Caiazzo, Ilaria and Turolla, Roberto and Veledina, Alexandra and Weisskopf, Martin C. and Forsblom, Sofia V. and González-Caniulef, Denis and Loktev, Vladislav and Malacaria, Christian and Mushtukov, Alexander A. and Suleimanov, Valery F. and Lutovinov, Alexander A. and Mereminskiy, Ilya A. and Molkov, Sergey V. and Salganik, Alexander and Santangelo, Andrea and Berdyugin, Andrei V. and Kravtsov, Vadim and Nitindala, Anagha P. and Agudo, Iván and Antonelli, Lucio A. and Bachetti, Matteo and Baldini, Luca and Baumgartner, Wayne H. and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D. and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Cavazzuti, Elisabetta and Chen, Chien-Ting and Ciprini, Stefano and Costa, Enrico and De Rosa, Alessandra and Del Monte, Ettore and Di Gesu, Laura and Di Lalla, Niccolò and Di Marco, Alessandro and Donnarumma, Immacolata and Dovčiak, Michal and Ehlert, Steven R. and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and García, Javier A. and Gunji, Shuichi and Hayashida, Kiyoshi and Iwakiri, Wataru and Jorstad, Svetlana G. and Kaaret, Philip and Karas, Vladimir and Kislat, Fabian and Kitaguchi, Takao and Kolodziejczak, Jeffery J. and Krawczynski, Henric and La Monaca, Fabio and Latronico, Luca and Liodakis, Ioannis and Maldera, Simone and Manfreda, Alberto and Marin, Frédéric and Marinucci, Andrea and Marscher, Alan P. and Marshall, Herman L. and Massaro, Francesco and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Muleri, Fabio and Negro, Michela and Ng, Chi-Yung and O’Dell, Stephen L. and Omodei, Nicola and Oppedisano, Chiara and Papitto, Alessandro and Pavlov, George G. and Peirson, Abel L. and Perri, Matteo and Pesce-Rollins, Melissa and Petrucci, Pierre-Olivier and Pilia, Maura and Possenti, Andrea and Puccetti, Simonetta and Ramsey, Brian D. and Rankin, John and Ratheesh, Ajay and Roberts, Oliver J. and Romani, Roger W. and Sgrò, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria and Swartz, Douglas A. and Tamagawa, Toru and Tavecchio, Fabrizio and Taverna, Roberto and Tawara, Yuzuru and Tennant, Allyn F. and Thomas, Nicholas E. and Tombesi, Francesco and Trois, Alessio and Vink, Jacco and Wu, Kinwah and Xie, Fei and Zane, Silvia},
issn = {1432-0746},
journal = {Astronomy & Astrophysics},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
publisher = {EDP Sciences},
title = {{Complex variations in X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431}},
doi = {10.1051/0004-6361/202347088},
volume = {677},
year = {2023},
}
@article{15194,
abstract = {AM Canum Venaticorum (AM CVn) systems are ultracompact binaries where a white dwarf accretes from a helium-rich degenerate or semidegenerate donor. Some AM CVn systems will be among the loudest sources of gravitational waves for the upcoming Laser Interferometer Space Antenna; yet the formation channel of AM CVns remains uncertain. We report the study and characterization of a new eclipsing AM CVn, SRGeJ045359.9+622444 (hereafter, SRGeJ0453), discovered from a joint Spektrum-Roentgen-Gamma (SRG) Extended Roentgen Survey with an Imaging Telescope Array (eROSITA) mission and Zwicky Transient Facility program to identify cataclysmic variables (CVs). We obtained optical photometry to confirm the eclipse of SRGeJ0453 and determine the orbital period to be
. We constrain the binary parameters by modeling the high-speed photometry and radial-velocity curves and find Mdonor = 0.044 ± 0.024M⊙ and Rdonor = 0.078 ± 0.012R⊙. The X-ray spectrum is approximated by a power-law model with an unusually flat photon index of Γ ∼ 1 previously seen in magnetic CVs with SRG/eROSITA, but verifying that the magnetic nature of SRGeJ0453 requires further investigation. Optical spectroscopy suggests that the donor star of SRGeJ0453 could have initially been a He star or a He white dwarf. SRGeJ0453 is the ninth eclipsing AM CVn system published to date, and its lack of optical outbursts have made it elusive in previous surveys. The discovery of SRGeJ0453 using joint X-ray and optical surveys highlights the potential for discovering similar systems in the near future.},
author = {Rodriguez, Antonio C. and Galiullin, Ilkham and Gilfanov, Marat and Kulkarni, Shrinivas R. and Khamitov, Irek and Bikmaev, Ilfan and van Roestel, Jan and Yungelson, Lev and El-Badry, Kareem and Sunayev, Rashid and Prince, Thomas A. and Buntov, Mikhail and Caiazzo, Ilaria and Drake, Andrew and Gorbachev, Mark and Graham, Matthew J. and Gumerov, Rustam and Irtuganov, Eldar and Laher, Russ R. and Masci, Frank J. and Medvedev, Pavel and Purdum, Josiah and Sakhibullin, Nail and Sklyanov, Alexander and Smith, Roger and Szkody, Paula and Vanderbosch, Zachary P.},
issn = {1538-4357},
journal = {The Astrophysical Journal},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {1},
publisher = {American Astronomical Society},
title = {{SRGeJ045359.9+622444: A 55 minute period eclipsing AM Canum Venaticorum star discovered from a joint SRG/eROSITA + ZTF search}},
doi = {10.3847/1538-4357/ace698},
volume = {954},
year = {2023},
}
@article{15195,
abstract = {White dwarfs, the extremely dense remnants left behind by most stars after their death, are characterized by a mass comparable to that of the Sun compressed into the size of an Earth-like planet. In the resulting strong gravity, heavy elements sink towards the centre and the upper layer of the atmosphere contains only the lightest element present, usually hydrogen or helium1,2. Several mechanisms compete with gravitational settling to change a white dwarf’s surface composition as it cools3, and the fraction of white dwarfs with helium atmospheres is known to increase by a factor of about 2.5 below a temperature of about 30,000 kelvin4,5,6,7,8; therefore, some white dwarfs that appear to have hydrogen-dominated atmospheres above 30,000 kelvin are bound to transition to be helium-dominated as they cool below it. Here we report observations of ZTF J203349.8+322901.1, a transitioning white dwarf with two faces: one side of its atmosphere is dominated by hydrogen and the other one by helium. This peculiar nature is probably caused by the presence of a small magnetic field, which creates an inhomogeneity in temperature, pressure or mixing strength over the surface9,10,11. ZTF J203349.8+322901.1 might be the most extreme member of a class of magnetic, transitioning white dwarfs—together with GD 323 (ref. 12), a white dwarf that shows similar but much more subtle variations. This class of white dwarfs could help shed light on the physical mechanisms behind the spectral evolution of white dwarfs.},
author = {Caiazzo, Ilaria and Burdge, Kevin B. and Tremblay, Pier-Emmanuel and Fuller, James and Ferrario, Lilia and Gänsicke, Boris T. and Hermes, J. J. and Heyl, Jeremy and Kawka, Adela and Kulkarni, S. R. and Marsh, Thomas R. and Mróz, Przemek and Prince, Thomas A. and Richer, Harvey B. and Rodriguez, Antonio C. and van Roestel, Jan and Vanderbosch, Zachary P. and Vennes, Stéphane and Wickramasinghe, Dayal and Dhillon, Vikram S. and Littlefair, Stuart P. and Munday, James and Pelisoli, Ingrid and Perley, Daniel and Bellm, Eric C. and Breedt, Elmé and Brown, Alex J. and Dekany, Richard and Drake, Andrew and Dyer, Martin J. and Graham, Matthew J. and Green, Matthew J. and Laher, Russ R. and Kerry, Paul and Parsons, Steven G. and Riddle, Reed L. and Rusholme, Ben and Sahman, Dave I.},
issn = {1476-4687},
journal = {Nature},
number = {7972},
pages = {61--66},
publisher = {Springer Nature},
title = {{A rotating white dwarf shows different compositions on its opposite faces}},
doi = {10.1038/s41586-023-06171-9},
volume = {620},
year = {2023},
}
@article{15196,
abstract = {We report the discovery of ZTF J0127+5258, a compact mass-transferring binary with an orbital period of 13.7 minutes. The system contains a white dwarf accretor, which likely originated as a post–common envelope carbon–oxygen (CO) white dwarf, and a warm donor (Teff,donor = 16,400 ± 1000 K). The donor probably formed during a common envelope phase between the CO white dwarf and an evolving giant that left behind a helium star or white dwarf in a close orbit with the CO white dwarf. We measure gravitational wave–driven orbital inspiral with ∼51σ significance, which yields a joint constraint on the component masses and mass transfer rate. While the accretion disk in the system is dominated by ionized helium emission, the donor exhibits a mixture of hydrogen and helium absorption lines. Phase-resolved spectroscopy yields a donor radial velocity semiamplitude of 771 ± 27 km s−1, and high-speed photometry reveals that the system is eclipsing. We detect a Chandra X-ray counterpart with LX ∼ 3 × 1031 erg s−1. Depending on the mass transfer rate, the system will likely either evolve into a stably mass-transferring helium cataclysmic variable, merge to become an R CrB star, or explode as a Type Ia supernova in the next million years. We predict that the Laser Space Interferometer Antenna (LISA) will detect the source with a signal-to-noise ratio of 24 ± 6 after 4 yr of observations. The system is the first LISA-loud mass-transferring binary with an intrinsically luminous donor, a class of sources that provide the opportunity to leverage the synergy between optical and infrared time domain surveys, X-ray facilities, and gravitational-wave observatories to probe general relativity, accretion physics, and binary evolution.},
author = {Burdge, Kevin B. and El-Badry, Kareem and Rappaport, Saul and Sunny Wong, Tin Long and Bauer, Evan B. and Bildsten, Lars and Caiazzo, Ilaria and Chakrabarty, Deepto and Chickles, Emma and Graham, Matthew J. and Kara, Erin and Kulkarni, S. R. and Marsh, Thomas R. and Nynka, Melania and Prince, Thomas A. and Simcoe, Robert A. and van Roestel, Jan and Vanderbosch, Zach and Bellm, Eric C. and Dekany, Richard G. and Drake, Andrew J. and Helou, George and Masci, Frank J. and Milburn, Jennifer and Riddle, Reed and Rusholme, Ben and Smith, Roger},
issn = {2041-8213},
journal = {The Astrophysical Journal Letters},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {1},
publisher = {American Astronomical Society},
title = {{Orbital decay in an accreting and eclipsing 13.7 minute orbital period binary with a luminous donor}},
doi = {10.3847/2041-8213/ace7cf},
volume = {953},
year = {2023},
}
@article{15197,
abstract = {Recently, the inner main belt asteroid (152830) Dinkinesh was identified as an additional fly- by target for the Lucy mission. The heliocentric orbit and approximate absolute magnitude of Dinkinesh are known, but little additional information was available prior to its selection as a target. In particular, the lack of color spectrophotometry or spectra made it impossible to assign a spectral type to Dinkinesh from which its albedo could be estimated. We set out to remedy this knowledge gap by obtaining visible wavelength spectra with the Keck telescope on 2022 November 23 and with Gemini-South on 2022 December 27. The spectra measured with the Keck I/Low Resolution Imaging Spectrometer (LRIS) and the Gemini South/Gemini Multi-Object Spectrograph South (GMOS-S) are most similar to the average spectrum of S- and Sq-type asteroids. The most diagnostic feature is the ≈15 ± 1% silicate absorption feature at ≈0.9–1.0 μm. Small S- and Sq-type asteroids have moderately high albedos ranging from 0.17 to 0.35. Using this albedo range for Dinkinesh in combination with measured absolute magnitude, it is possible to derive an effective diameter and surface brightness for this body. The albedo, size and surface brightness are important inputs required for planning a successful encounter by the Lucy spacecraft.},
author = {Bolin, B.T. and Noll, K.S. and Caiazzo, Ilaria and Fremling, C. and Binzel, R.P.},
issn = {0019-1035},
journal = {Icarus},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
publisher = {Elsevier},
title = {{Keck and Gemini spectral characterization of Lucy mission fly-by target (152830) Dinkinesh}},
doi = {10.1016/j.icarus.2023.115562},
volume = {400},
year = {2023},
}
@article{15198,
abstract = {The axion-nucleon coupling enables the production of axions through the decay of excited 57Fe nuclei, and axions produced in the Sun through this process are often a target of helioscope searches. We show for the first time that hot, highly magnetic white dwarfs such as ZTF J1901+1458 are a viable target to search for the x-ray signature of axions that were produced by the 57Fe transition in the core and then converted to photons in the magnetosphere. We calculate that a 100 ks observation of ZTF J1901+1458 with NuSTAR would constrain the coupling of axions to nucleons and photons at a level below the bounds of both current and future planned helioscopes.},
author = {Fleury, Leesa and Caiazzo, Ilaria and Heyl, Jeremy},
issn = {2470-0029},
journal = {Physical Review D},
number = {10},
publisher = {American Physical Society},
title = {{Constraining axions with ZTF J1901+1458}},
doi = {10.1103/physrevd.107.l101303},
volume = {107},
year = {2023},
}
@article{15199,
abstract = {Gaia Data Release 2 revealed a population of ultramassive white dwarfs on the Q branch that are moving anomalously fast for a local disc population with their young photometric ages. As the velocity dispersion of stars in the local disc increases with age, a proposed explanation of these white dwarfs is that they experience a cooling delay that causes current cooling models to infer photometric ages much younger than their true ages. To explore this explanation, we investigate the kinematics of ultramassive white dwarfs within 200 pc of the Sun using the improved Gaia Early Data Release 3 observations. We analyse the transverse motions of 0.95–1.25 M⊙ white dwarfs, subdivided by mass and age, and determine the distributions of the three-dimensional components of the transverse velocities. The results are compared to expectations based on observed kinematics of local main-sequence stars. We find a population of photometrically young (∼0.5–1.5 Gyr) ultramassive (∼1.15–1.25 M⊙) white dwarfs for which the transverse velocity component in the direction of Galactic rotation is more dispersed than for local disc stars of any age; thus, it is too dispersed to be explained by any cooling delay in white dwarfs originating from the local disc. Furthermore, the dispersion ratio of the velocity components in the Galactic plane for this population is also inconsistent with a local disc origin. We discuss some possible explanations of this kinematically anomalous population, such as a halo origin or production through dynamical effects of stellar triple systems.},
author = {Fleury, Leesa and Caiazzo, Ilaria and Heyl, Jeremy},
issn = {1365-2966},
journal = {Monthly Notices of the Royal Astronomical Society},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {1},
pages = {364--374},
publisher = {Oxford University Press},
title = {{The origin of ultramassive white dwarfs: hints from Gaia EDR3}},
doi = {10.1093/mnras/stad068},
volume = {520},
year = {2023},
}
@article{15200,
abstract = {Magnetic cataclysmic variables (CVs) are luminous Galactic X-ray sources, which have been difficult to find in purely optical surveys due to their lack of outburst behavior. The eROSITA telescope on board the Spektr-RG mission is conducting an all-sky X-ray survey and recently released the public eROSITA Final Equatorial Depth Survey (eFEDS) catalog. We crossmatched the eFEDS catalog with photometry from the Zwicky Transient Facility and discovered two new magnetic CVs. We obtained high-cadence optical photometry and phase-resolved spectroscopy for each magnetic CV candidate and found them both to be polars. Among the newly discovered magnetic CVs is eFEDS J085037.2+044359/ZTFJ0850+0443, an eclipsing polar with orbital period Porb = 1.72 hr and WD mass MWD = 0.81 ± 0.08M⊙. We suggest that eFEDS J085037.2+044359/ZTFJ0850+0443 is a low magnetic field strength polar, with BWD ≲ 10 MG. We also discovered a non-eclipsing polar, eFEDS J092614.1+010558/ZTFJ0926+0105, with orbital period Porb = 1.47 hr and magnetic field strength BWD = 36–42 MG.},
author = {Rodriguez, Antonio C. and Kulkarni, Shrinivas R. and Prince, Thomas A. and Szkody, Paula and Burdge, Kevin B. and Caiazzo, Ilaria and van Roestel, Jan and Vanderbosch, Zachary P. and El-Badry, Kareem and Bellm, Eric C. and Gänsicke, Boris T. and Graham, Matthew J. and Mahabal, Ashish A. and Masci, Frank J. and Mróz, Przemek and Riddle, Reed and Rusholme, Ben},
issn = {1538-4357},
journal = {The Astrophysical Journal},
keywords = {Space and Planetary Science, Astronomy and Astrophysics},
number = {2},
publisher = {American Astronomical Society},
title = {{Discovery of two polars from a crossmatch of ZTF and the SRG/eFEDS x-ray catalog}},
doi = {10.3847/1538-4357/acbb6f},
volume = {945},
year = {2023},
}