olozhika / ArXivDaily_StarFormation

Auto update Star Formation & Molecular Cloud papers at about 2:30am UTC (10:30am Beijing time) every weekday.

New submissions for Wednesday, 31 July 2024

Auto update Star Formation & Molecular Cloud papers at about 2:30am UTC (10:30am Beijing time) every weekday.

阅读 Usage.md了解如何使用此repo实现个性化的Arxiv论文推送

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Keyword list: ['star formation', 'star-forming', 'molecular cloud', 'interstellar medium', 'cloud', 'clump', 'core', 'filament', 'atomic gas', 'N-PDF']

Excluded: ['galaxies', 'galaxy cluster', ' AGN ']

Today: 10papers

Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-Velocity Data

• Authors: Mona El Morsy, Thayne Currie, Danielle Bovie, Masayuki Kuzuhara, Brianna Lacy, Yiting Li, Taylor Tobin, Timothy Brandt, Jeffrey Chilcote, Olivier Guyon, Tyler Groff, Julien Lozi, Sebastien Vievard, Vincent Deo, Nour Skaf, Francois Bouchy, Isabelle Boisse, Erica Dykes, N. J. Kasdin, Motohide Tamura

• Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2407.20322

• Pdf link: https://arxiv.org/pdf/2407.20322

• Abstract We present follow-up SCExAO/CHARIS $H$ and $K$-band (R $\sim$ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly-imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the SOPHIE spectrograph, complemented by Hipparcos and Gaia astrometry. These data enable more robust spectral characterization compared to lower-resolution spectra from the discovery paper and more than double the available astrometric and radial-velocity baseline. HD 33632 Ab's spectrum is well reproduced by a field L8.5--L9.5 dwarf. Using the Exo-REM atmosphere models, we derive a best-fit temperature, surface gravity and radius of $T_{\rm eff}$ = 1250 $K$, log(g) = 5, and $R$ = 0.97 $R_{\rm J}$ and a solar C/O ratio. Adding the SOPHIE radial-velocity data enables far tighter constraints on the companion's orbital properties (e.g. $i$=${46.6}{-5.7}^{+2.9}$$^{o}$) and dynamical mass (${51.7}{-2.5}^{+2.6}$$M_{\rm J}$) than derived from imaging data and \textit{Gaia} eDR3 astrometry data alone. HD 33632 Ab should be a prime target for multi-band imaging and spectroscopy with the James Webb Space Telescope and the Roman Space Telescope's Coronagraphic Instrument, shedding detailed light on HD 33632 Ab's clouds and chemistry and providing a key reference point for understanding young exoplanet atmospheres.

Probing the Magnetised Gas Distribution in Galaxy Groups and the Cosmic Web with POSSUM Faraday Rotation Measures

• Authors: Craig S. Anderson, N. M. McClure-Griffiths, L. Rudnick, B. M. Gaensler, S. P. O'Sullivan, S. Bradbury, T. Akahori, L. Baidoo, M. Bruggen, E. Carretti, S. Duchesne, G. Heald, S. L. Jung, J. Kaczmarek, D. Leahy, F. Loi, Y. K. Ma, E. Osinga, A. Seta, C. Stuardi, A. J. M. Thomson, C. Van Eck, T. Vernstrom, J. West

• Subjects: Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

• Arxiv link: https://arxiv.org/abs/2407.20325

• Pdf link: https://arxiv.org/pdf/2407.20325

• Abstract We present initial results from the Polarisation Sky Survey of the Universe's Magnetism (POSSUM), analysing 22,817 Faraday Rotation Measures (RMs) with median uncertainties of 1.2 rad m^-2 across 1,520 square degrees to study magnetised gas associated with 55 nearby galaxy groups (z less than 0.025) with halo masses between 10^12.5 and 10^14.0 M_sun. We identify two distinct gas phases: the Intragroup Medium (IGrM) within 0-2 splashback radii and the Warm-Hot Intergalactic Medium (WHIM) extending from 2 to 7 splashback radii. These phases enhance the standard deviation of residual (i.e., Galactic foreground RM-subtracted) RMs by 6.9 +/- 1.8 rad m^-2 and 4.2 +/- 1.2 rad m^-2, respectively. Estimated magnetic field strengths are several microGauss within the IGrM and 0.1-1 microGauss in the WHIM. We estimate the plasma beta in both phases and show that magnetic pressure might be more dynamically important than in the ICM of more massive clusters or sparse cosmic web filaments. Our findings indicate that "missing baryons" in the WHIM likely extend beyond the gravitational radii of group-mass halos to Mpc scales, consistent with large-scale, outflow-driven "magnetised bubbles" seen in cosmological simulations. We demonstrate that RM grids are an effective method for detecting magnetised thermal gas at galaxy group interfaces and within the cosmic web. This approach complements X-ray and Sunyaev-Zel'dovich effect methods, and when combined with Fast Radio Burst Dispersion Measures, data from the full POSSUM survey, comprising approximately a million RMs, will allow direct magnetic field measurements to further our understanding of baryon circulation in these environments and the magnetised universe.

Evolution of Extremely Soft Binaries in Dense Star Clusters: On the Jupiter Mass Binary Objects

• Authors: Yihan Wang, Rosalba Perna, Zhaohuan Zhu, Douglas N. C. Lin

• Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2407.20416

• Pdf link: https://arxiv.org/pdf/2407.20416

• Abstract Star-forming regions, characterized by dense environments, experience frequent encounters that significantly influence binary systems, leading to their hardening, softening, or ionization. We extend the Hut & Bahcall formalism to derive an analytical expression for the ionization cross-section in extreme mass ratio binary systems, allowing us to investigate the orbital evolution and population dynamics of binary planets and binary brown dwarfs in star clusters, while considering ongoing binary system formation. Our findings reveal that for low-mass soft binaries, the semi-major axis distribution asymptotes to a universal power law between $\propto a^{-8/3}$ and $\propto a^{-5/3}$ over the derived ionization timescale. We also discuss the implications of our results for the candidate Jupiter-mass binary objects putatively reported in the Trapezium cluster. We demonstrate that if their existence is verified, they likely form continuously with a spectrum proportional to $a^{1}$, aligning better with the ejection mechanism than with the in-situ formation mechanism, which predicts a distribution roughly proportional to $a^{-1}$. However, this implies an impractically high ejection formation rate. Alternatively, if these objects are binary brown dwarfs, continuous in-situ formation ($\propto a^{-1}$) with an initial minimal semi-major axis around 20 AU and a formation rate of 100 Myr$^{-1}$ plausibly matches the observed number of single objects, binary number, binary fraction, and semi-major axis distribution.

The effects of surface fossil magnetic fields on massive star evolution: V. Models at low metallicity

• Authors: Z. Keszthelyi, J. Puls, G. Chiaki, H. Nagakura, A. ud-Doula, T. Takiwaki, N. Tominaga

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2407.20492

• Pdf link: https://arxiv.org/pdf/2407.20492

• Abstract At metallicities lower than that of the Small Magellanic Cloud, it remains essentially unexplored how fossil magnetic fields, forming large-scale magnetospheres, could affect the evolution of massive stars, thereby impacting the fundamental building blocks of the early Universe. We extend our stellar evolution model grid with representative calculations of main-sequence, single-star models with initial masses of 20 and 60 M$\odot$, including appropriate changes for low-metallicity environments ($Z = 10^{-3}-10^{-6}$). We scrutinise the magnetic, rotational, and chemical properties of the models. When lowering the metallicity, the rotational velocities can become higher and the tendency towards quasi-chemically homogeneous evolution increases. While magnetic fields aim to prevent the development of this evolutionary channel, the weakening stellar winds lead to less efficient magnetic braking in our models. Since the stellar radius is almost constant during a blueward evolution caused by efficient chemical mixing, the surface magnetic field strength remains unchanged in some models. We find core masses at the terminal-age main sequence between 22 and 52 M$\odot$ for initially 60 M$_\odot$ models. This large difference is due to the vastly different chemical and rotational evolution. We conclude that in order to explain chemical species and, in particular, high nitrogen abundances in the early Universe, the adopted stellar models need to be under scrutiny. The assumptions regarding wind physics, chemical mixing, and magnetic fields will strongly impact the model predictions.

Inspecting neutrino flavor instabilities during proto-neutron star cooling phase in supernova: I. Spherically symmetric model

• Authors: Masamichi Zaizen, Sherwood Richers, Hiroki Nagakura, Hideyuki Suzuki, Chinami Kato

• Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

• Arxiv link: https://arxiv.org/abs/2407.20548

• Pdf link: https://arxiv.org/pdf/2407.20548

• Abstract In the standard model of core-collapse supernova (CCSN), all neutrinos are assumed to be in pure flavor eigenstates in CCSN cores, but the assumption becomes invalid if neutrino distributions are unstable to flavor conversions. In this paper, we present a study of the occurrences of two representative neutrino-flavor instabilities, fast- and collisional flavor instabilities, in the cooling phase of proto-neutron star (PNS) from 1- to 50 seconds. We follow the long-term evolution of a PNS under spherically symmetric and quasi-static approximations, in which the matter profile is determined by solving the Tolman-Oppenheimer-Volkoff equation with neutrino feedback under the treatment of multi-group flux limited diffusion. For the stability analysis of neutrino flavor conversions, we recompute neutrino distributions using Monte Carlo transport in order to obtain the full angular distribution needed to compute the dispersion relations. We find no signs of flavor conversions in our models; the physical reason is thoroughly investigated. We also argue that the negative conclusion in flavor conversions could be changed qualitatively if multi-dimensional effects are included, as similar to cases in the earlier phase of CCSN.

The Fourth S-PLUS Data Release: 12-filter photometry covering $\sim3000$ square degrees in the southern hemisphere

• Authors: Fabio R. Herpich, Felipe Almeida-Fernandes, Gustavo B. Oliveira Schwarz, Erik V. R. Lima, Lilianne Nakazono, Javier Alonso-García, Marcos A. Fonseca-Faria, Marilia J. Sartori, Guilherme F. Bolutavicius, Gabriel Fabiano de Souza, Eduardo A. Hartmann, Liana Li, Luna Espinosa, Antonio Kanaan, William Schoenell, Ariel Werle, Eduardo Machado-Pereira, Luis A. Gutiérrez-Soto, Thaís Santos-Silva, Analia V. Smith Castelli, Eduardo A. D. Lacerda, Cassio L. Barbosa, Hélio D. Perottoni, Carlos E. Ferreira Lopes, Raquel Ruiz Valença, Pierre Augusto Re Martho, Clecio R. Bom, Charles J. Bonatto, Maiara S. Carvalho, Vitor Cernic, Roberto Cid Fernandes, Paula Coelho, Ariana Cortesi, Barbara Cubillos Palma, Lia Doubrawa, Vincenzo Sivero Ferreira Alberice, Fredi Quispe Huaynasi, Gabriel Jacob Perin, Marcelo Jaque Arancibia, Angela Krabbe, Ciria Lima-Dias, Luis Lomelí-Núñez, Raimundo Lopes de Oliveira, Amanda R. Lopes, André Luiz Figueiredo, Elismar Lösch, Felipe Navarete, Julia Mello de Oliveira, Roderik Overzier, Vinicius M. Placco, Fernando V. Roig, Mariana Rubet, André Santos, Victor Hugo Sasse, Julia Thaina-Batista, Sergio Torres-Flores, Timothy C. Beers, Alvaro Alvarez-Candal, Stavros Akras, Swayamtrupta Panda, Guilherme Limberg, José Luis Nilo Castellón, Eduardo Telles, Paulo Afranio Lopes, Gissel Dayana Pardo Montaguth, Leandro Beraldo e Silva, Pedro K. Humire, Marcelo Borges Fernandes, Vinícius Cordeiro, Tiago Ribeiro, Claudia Mendes de Oliveira

• Subjects: Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2407.20701

• Pdf link: https://arxiv.org/pdf/2407.20701

• Abstract The Southern Photometric Local Universe Survey (S-PLUS) is a project to map $\sim9300$ sq deg of the sky using twelve bands (seven narrow and five broadbands). Observations are performed with the T80-South telescope, a robotic telescope located at the Cerro Tololo Observatory in Chile. The survey footprint consists of several large contiguous areas, including fields at high and low galactic latitudes, and towards the Magellanic Clouds. S-PLUS uses fixed exposure times to reach point source depths of about $21$ mag in the $griz$ and $20$ mag in the $u$ and the narrow filters. This paper describes the S-PLUS Data Release 4 (DR4), which includes calibrated images and derived catalogues for over 3000 sq deg, covering the aforementioned area. The catalogues provide multi-band photometry performed with the tools \texttt{DoPHOT} and \texttt{SExtractor} -- point spread function (\PSF) and aperture photometry, respectively. In addition to the characterization, we also present the scientific potential of the data. We use statistical tools to present and compare the photometry obtained through different methods. Overall we find good agreement between the different methods, with a slight systematic offset of 0.05,mag between our \PSF and aperture photometry. We show that the astrometry accuracy is equivalent to that obtained in previous S-PLUS data releases, even in very crowded fields where photometric extraction is challenging. The depths of main survey (MS) photometry for a minimum signal-to-noise ratio $S/N = 3$ reach from $\sim19.5$ for the bluer bands to $\sim21.5$ mag on the red. The range of magnitudes over which accurate \PSF photometry is obtained is shallower, reaching $\sim19$ to $\sim20.5$ mag depending on the filter. Based on these photometric data, we provide star-galaxy-quasar classification and photometric redshift for millions of objects.

Barb'a 2: A new supergiant-rich Galactic stellar cluster

• Authors: J. Maíz Apellániz, I. Negueruela

• Subjects: Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2407.20812

• Pdf link: https://arxiv.org/pdf/2407.20812

• Abstract We present a new supergiant-rich stellar cluster hidden by extinction and christen it as Barbá 2, in honor of its discoverer Rodolfo Barbá. The cluster is at a distance of $7.39^{+0.65}{-0.55}$ kpc and contains several supergiants, of which we provide spectral classifications for one blue, one yellow, and five red ones. The cluster extinction indicates an above-average grain-size ($R{5495} \sim 3.7$), its age has a minimum value of 10 Ma, and its core radius is $0.84\pm0.19$ pc.

On the use of field RR Lyrae as Galactic probes VII. light curve templates in the LSST photometric system

• Authors: V.F. Braga (1,2), M. Monelli (1), M. Dall'Ora (3), J.P. Mullen (4), R. Molinaro (3), M. Marconi (3), R. Szabó (5,6,7), C. Gallart (1) ((1) Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain, (2) INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy, (3) INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy, (4) Department of Physics and Astronomy, Vanderbilt University, Nashville, USA, (5) Konkoly Observatory, Research Centre for Astronomy and Earth Sciences (ELKH), Budapest, Hungary, (6) MTA CSFK Lendület Near-Field Cosmology Research Group, Budapest, Hungary, (7) ELTE Eötvös Loránd University, Institute of Physics, Budapest, Hungary)

• Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

• Arxiv link: https://arxiv.org/abs/2407.20813

• Pdf link: https://arxiv.org/pdf/2407.20813

• Abstract The \textit{Vera C. Rubin} Observatory will start operations in 2025. During the first two years, too few visits per target per band will be available, meaning that mean magnitude measurements of variable stars will not be precise and thus, standard candles like RR Lyrae (RRL) will not be usable. Light curve templates (LCTs) can be adopted to estimate the mean magnitude of a variable star with few magnitude measurements, provided that their period (plus amplitude and reference epoch, depending on how the LCT is applied) is known. LSST will provide precise RRL periods within the first six months, allowing to exploit RRLs if LCTs were available. We aim to build LCTs in the LSST bands to enhance the early science with LSST. Using them will provide a 1-2 years advantage with respect to a classical approach, concerning distance measurements. We collected $gri$-band data from the ZTF survey and $z$-band data from DECam to build the LCTs of RRLs. We also adopted synthetic $griz$-band data in the LSST system from pulsation models, plus SDSS, \gaia and OGLE photometry, inspecting the light amplitude ratios in different photometric systems to provide useful conversions to apply the LCTs. We have built LCTs of RRLs in the $griz$ bands of the LSST photometric system; for the $z$ band, we could build only fundamental-mode RRL LCTs. We quantitatively demonstrated that LCTs built with ZTF and DECam data can be adopted on the LSST photometric system. LCTs will decrease by a factor of at least two the uncertainty on distance estimates of RRLs, with respect to a simple average of the available measurements. Finally, within our tests, we have found a brand new behavior of amplitude ratios in the Large Magellanic Cloud.

Atmospheric characterization of the super-Jupiter HIP 99770 b with KPIC

• Authors: Yapeng Zhang, Jerry W. Xuan, Dimitri Mawet, Jason J. Wang, Chih-Chun Hsu, Jean-Bapiste Ruffio, Heather A. Knutson, Julie Inglis, Geoffrey A. Blake, Yayaati Chachan, Katelyn Horstman, Ashley Baker, Randall Bartos, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Greg Doppmann, Daniel Echeverri, Luke Finnerty, Michael P. Fitzgerald, Nemanja Jovanovic, Joshua Liberman, Ronald A. López, Evan Morris, Jacklyn Pezzato, Ben Sappey, Tobias Schofield, Andrew Skemer, J. Kent Wallace, Ji Wang, Clarissa R. Do Ó

• Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2407.20952

• Pdf link: https://arxiv.org/pdf/2407.20952

• Abstract Young, self-luminous super-Jovian companions discovered by direct imaging provide a challenging test of planet formation and evolution theories. By spectroscopically characterizing the atmospheric compositions of these super-Jupiters, we can constrain their formation histories. Here we present studies of the recently discovered HIP 99770 b, a 16 MJup high-contrast companion on a 17 au orbit, using the fiber-fed high-resolution spectrograph KPIC (R~35,000) on the Keck II telescope. Our K-band observations led to detections of H2O and CO in the atmosphere of HIP 99770 b. We carried out free retrieval analyses using petitRADTRANS to measure its chemical abundances, including the metallicity and C/O ratio, projected rotation velocity (vsini), and radial velocity (RV). We found that the companion's atmosphere has C/O=0.55(-0.04/+0.06) and [M/H]=0.26(-0.23/+0.24) (1{\sigma} confidence intervals), values consistent with those of the Sun and with a companion formation via gravitational instability or core accretion. The projected rotation velocity < 7.8 km/s is small relative to other directly imaged companions with similar masses and ages. This may imply a near pole-on orientation or effective magnetic braking by a circumplanetary disk. In addition, we added the companion-to-primary relative RV measurement to the orbital fitting and obtained updated constraints on orbital parameters. Detailed characterization of super-Jovian companions within 20 au like HIP 99770 b is critical for understanding the formation histories of this population.

Recent Update of Gas-Phase Chemical Reactions and Molecular Lines of TiO in Cloudy

• Authors: Gargi Shaw, Gary J. Ferland, Phillip Stancil, Ryan Porter

• Subjects: Subjects: Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2407.20972

• Pdf link: https://arxiv.org/pdf/2407.20972

• Abstract We present our current update on the gas-phase chemical reactions and spectral lines of TiO in the spectral synthesis code Cloudy. For this purpose, we have added 229 Ti-related reactions in the chemical network. In addition, we consider 230 fine-structure energy levels, the corresponding 223 radiative transitions, and 444 collisional transitions with ortho and para H$_2$ and predict 66 TiO lines. We perform spectroscopic simulations of TiO emission from the circumstellar region of the oxygen-rich red supergiant VY Canis Majoris to validate our update. Our model reproduces the observed TiO column density. This update is helpful in modeling dust-free astrophysical environments where Ti is in the gas phase and TiO can form.

by olozhika (Xing Yuchen).

2024-07-31