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First detection of ultra-high energy emission from gamma-ray binary LS I +61 303

We report the first detection of gamma-ray emission up to ultra-high-energy (UHE; $>$100 TeV) emission from the prototypical gamma-ray binary system LS I +61 303 using data from the Large High Altitude Air Shower Observatory (LHAASO). It is…

High Energy Astrophysical Phenomena · Physics 2026-03-12 Zhen Cao , F. Aharonian , Y. X. Bai , Y. W. Bao , D. Bastieri , X. J. Bi , Y. J. Bi , W. Bian , J. Blunier , A. V. Bukevich , C. M. Cai , Y. Y. Cai , W. Y. Cao , Zhe Cao , J. Chang , J. F. Chang , E. S. Chen , G. H. Chen , H. K. Chen , L. F. Chen , Liang Chen , Long Chen , M. J. Chen , M. L. Chen , Q. H. Chen , S. Chen , S. H. Chen , S. Z. Chen , T. L. Chen , X. B. Chen , X. J. Chen , X. P. Chen , Y. Chen , N. Cheng , Q. Y. Cheng , Y. D. Cheng , M. Y. Cui , S. W. Cui , X. H. Cui , Y. D. Cui , B. Z. Dai , H. L. Dai , Z. G. Dai , Danzengluobu , Y. X. Diao , A. J. Dong , X. Q. Dong , K. K. Duan , J. H. Fan , Y. Z. Fan , J. Fang , J. H. Fang , K. Fang , C. F. Feng , H. Feng , L. Feng , S. H. Feng , X. T. Feng , Y. Feng , Y. L. Feng , S. Gabici , B. Gao , Q. Gao , W. Gao , W. K. Gao , M. M. Ge , T. T. Ge , L. S. Geng , G. Giacinti , G. H. Gong , Q. B. Gou , M. H. Gu , F. L. Guo , J. Guo , K. J. Guo , X. L. Guo , Y. Q. Guo , Y. Y. Guo , R. P. Han , O. A. Hannuksela , M. Hasan , H. H. He , H. N. He , J. Y. He , X. Y. He , Y. He , S. Hernández-Cadena , B. W. Hou , C. Hou , X. Hou , H. B. Hu , S. C. Hu , C. Huang , D. H. Huang , J. J. Huang , X. L. Huang , X. T. Huang , X. Y. Huang , Y. Huang , Y. Y. Huang , A. Inventar , X. L. Ji , H. Y. Jia , K. Jia , H. B. Jiang , K. Jiang , X. W. Jiang , Z. J. Jiang , M. Jin , S. Kaci , M. M. Kang , I. Karpikov , D. Khangulyan , D. Kuleshov , K. Kurinov , Cheng Li , Cong Li , D. Li , F. Li , H. B. Li , H. C. Li , Jian Li , Jie Li , K. Li , L. Li , R. L. Li , S. D. Li , T. Y. Li , W. L. Li , X. R. Li , Y. Li , Zhe Li , Zhuo Li , E. W. Liang , Y. F. Liang , S. J. Lin , B. Liu , C. Liu , D. Liu , D. B. Liu , H. Liu , J. Liu , J. L. Liu , J. R. Liu , M. Y. Liu , R. Y. Liu , S. M. Liu , W. Liu , X. Liu , Y. Liu , Y. Liu , Y. N. Liu , Y. Q. Lou , Q. Luo , Y. Luo , H. K. Lv , B. Q. Ma , L. L. Ma , X. H. Ma , I. O. Maliy , J. R. Mao , Z. Min , W. Mitthumsiri , Y. Mizuno , G. B. Mou , A. Neronov , K. C. Y. Ng , M. Y. Ni , L. Nie , L. J. Ou , Z. W. Ou , P. Pattarakijwanich , Z. Y. Pei , D. Y. Peng , J. C. Qi , M. Y. Qi , J. J. Qin , D. Qu , A. Raza , C. Y. Ren , D. Ruffolo , A. Sáiz , D. Savchenko , D. Semikoz , L. Shao , O. Shchegolev , Y. Z. Shen , X. D. Sheng , Z. D. Shi , F. W. Shu , H. C. Song , Yu. V. Stenkin , Y. Su , D. X. Sun , H. Sun , J. X. Sun , Q. N. Sun , X. N. Sun , Z. B. Sun , N. H. Tabasam , J. Takata , P. H. T. Tam , H. B. Tan , Q. W. Tang , R. Tang , Z. B. Tang , W. W. Tian , C. N. Tong , L. H. Wan , C. Wang , D. H. Wang , G. W. Wang , H. G. Wang , J. C. Wang , K. Wang , Kai Wang , Kai Wang , L. P. Wang , L. Y. Wang , L. Y. Wang , R. Wang , W. Wang , X. G. Wang , X. J. Wang , X. Y. Wang , Y. Wang , Y. D. Wang , Z. H. Wang , Z. X. Wang , Zheng Wang , D. M. Wei , J. J. Wei , Y. J. Wei , T. Wen , S. S. Weng , C. Y. Wu , H. R. Wu , Q. W. Wu , S. Wu , X. F. Wu , Y. S. Wu , S. Q. Xi , J. Xia , J. J. Xia , G. M. Xiang , D. X. Xiao , G. Xiao , Y. F. Xiao , Y. L. Xin , H. D. Xing , Y. Xing , D. R. Xiong , B. N. Xu , C. Y. Xu , D. L. Xu , R. F. Xu , R. X. Xu , S. S. Xu , W. L. Xu , L. Xue , D. H. Yan , T. Yan , C. W. Yang , C. Y. Yang , F. F. Yang , L. L. Yang , M. J. Yang , R. Z. Yang , W. X. Yang , Z. H. Yang , Z. G. Yao , X. A. Ye , L. Q. Yin , N. Yin , X. H. You , Z. Y. You , Q. Yuan , H. Yue , H. D. Zeng , T. X. Zeng , W. Zeng , X. T. Zeng , M. Zha , B. B. Zhang , B. T. Zhang , C. Zhang , H. Zhang , H. M. Zhang , H. Y. Zhang , J. L. Zhang , J. Y. Zhang , Li Zhang , P. F. Zhang , R. Zhang , S. R. Zhang , S. S. Zhang , S. Y. Zhang , W. Zhang , W. Y. Zhang , X. Zhang , X. P. Zhang , Yi Zhang , Yong Zhang , Z. P. Zhang , J. Zhao , L. Zhao , L. Z. Zhao , S. P. Zhao , X. H. Zhao , Z. H. Zhao , F. Zheng , T. C. Zheng , B. Zhou , H. Zhou , J. N. Zhou , M. Zhou , P. Zhou , R. Zhou , X. X. Zhou , X. X. Zhou , B. Y. Zhu , C. G. Zhu , F. R. Zhu , H. Zhu , K. J. Zhu , Y. C. Zou , X. Zuo

Active Stars in the Spectroscopic Survey of Mid-to-Late M Dwarfs Within 15pc

We present results from the volume-complete spectroscopic survey of 0.1-0.3M$_\odot$ M dwarfs within 15pc. This work discusses the active sample without close binary companions, providing a comprehensive picture of these 123 stars with…

Solar and Stellar Astrophysics · Physics 2023-06-28 Emily K Pass , Jennifer G Winters , David Charbonneau , Jonathan M Irwin , Amber A Medina

First Observation of de Haas-van Alphen Effect and Fermi Surfaces in Unconventional Superconductor UTe2

We report the first observation of the de Haas-van Alphen (dHvA) effect in the novel spin-triplet superconductor UTe2 using high quality single crystals with the high residual resistivity ratio (RRR) over 200. The dHvA frequencies, named…

Strongly Correlated Electrons · Physics 2022-07-18 Dai Aoki , Hironori Sakai , Petr Opletal , Yoshifumi Tokiwa , Jun Ishizuka , Youichi Yanase , Hisatomo Harima , Ai Nakamura , Dexin Li , Yoshiya Homma , Yusei Shimizu , Georg Knebel , Jacques Flouquet , Yoshinori Haga

Mass Outflow and Chromospheric Activity of Red Giant Stars in Globular Clusters I: M15

High resolution spectra of 110 selected red giant stars in the globular cluster M15 (NGC 7078) were obtained with Hectochelle at the MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders containing Halpha and Ca H & K are…

Astrophysics · Physics 2009-11-13 Sz. Meszaros , A. K. Dupree , A. Szentgyorgyi

Multiband photometric detection of a huge flare on the M9 dwarf 2MASSW J1707183+643933

We present simultaneous UV-G-R-I monitoring of 19 M dwarfs that revealed a huge flare on the M9 dwarf 2MASSW J1707183+643933 with an amplitude in the UV of at least 6 magnitudes. This is one of the strongest detections ever of an optical…

Astrophysics · Physics 2009-11-13 Boris Rockenfeller , Coryn A. L. Bailer-Jones , Reinhard Mundt , Mansur A. Ibrahimov

Rotation-Activity Relation of Ca II and Mg I Infrared Emission Lines of Young Stars

To reveal the detail of the internal structure, the relationship between chromospheric activity and the Rossby number, N_R (= rotational period P / convective turnover time tau_c), has been extensively examined for main-sequence stars. The…

Solar and Stellar Astrophysics · Physics 2021-05-26 Mai Yamashita , Yoichi Itoh , Yuhei Takagi

A long-duration flare in the X-ray/EUV selected chromospherically active binary 2RE J0743+224

2RE J0743+224 (BD +23 1799) is a chromospherically active star selected by X-rays and EUV emission detected in the Einstein Slew Survey and ROSAT Wide Field Camara (WFC) all sky survey, and classified as single-lined spectroscopic binary by…

Astrophysics · Physics 2007-05-23 D. Montes , L. W. Ramsey

Determining the magnetic field of active region plages using the whole CLASP2/2.1 spectral window

The Chromospheric LAyer SpectroPolarimeter missions, CLASP2 and CLASP2.1, demonstrated that the near-UV spectral region between 279.30 and 280.68 nm is suitable for studying the magnetism of the solar chromosphere. In particular, the…

Solar and Stellar Astrophysics · Physics 2025-08-21 David Afonso Delgado , Tanausú del Pino Alemán , Javier Trujillo Bueno , Ryohko Ishikawa , Ernest Alsina Ballester , David E. McKenzie , Luca Belluzzi , Christian Bethge , Ken Kobayashi , Takenori J. Okamoto , Laurel A. Rachmeler , Donguk Song , Jiří Śtěpán , Bart de Pontieu , Adam R. Kobelski , Genevieve D. Vigil , Frédéric Auchère , Ryouhei Kano , Amy Winebarger

Stellar activity with LAMOST - II. Chromospheric activity in open clusters

We use the LAMOST spectra of member stars in Pleiades, M34, Praesepe, and Hyades to study how chromospheric activity vary as a function of mass and rotation at different age. We measured excess equivalent widths of H$\alpha$, H$\beta$, and…

Solar and Stellar Astrophysics · Physics 2018-01-31 Xiang-Song Fang , Gang Zhao , Jing-Kun Zhao , Yerra Bharat Kumar

Discovery of a New Deeply Eclipsing SU UMa-Type Dwarf Nova, IY UMa (= TmzV85)

We discovered a new deeply eclipsing SU UMa-type dwarf nova, IY UMa, which experienced a superoutburst in 2000 January. Our monitoring revealed two distinct outbursts, which suggest a superoutburst interval of ~800 d, or its half, and an…

Astrophysics · Physics 2015-06-24 M. Uemura , T. Kato , K. Matsumoto , K. Takamizawa , P. Schmeer , L. T. Jensen , T. Vanmunster , R. Novak , B. Martin , J. Pietz , D. Buczynski , T. Kinnunen , M. Moilanen , A. Oksanen , Lewis M. Cook , T. Watanabe , H. Maehara , H. Itoh

On the lithium abundance dispersion in late-type Pleiades stars

I present the results of a programme to monitor the strengths of the Li I 6708A, K I 7699A and chromospheric Halpha lines in a group of cool Pleiades stars. Consistent instrumentation and analysis techniques are used to show that there is…

Astrophysics · Physics 2009-10-31 R. D. Jeffries

Infrared spectropolarimetry of a C-class solar flare footpoint plasma -- I. Spectral features and forward modelling

We performed high-spatial resolution spectropolarimetric observations of active region NOAA 13363 during a C-class flare with the Gregor Infrared Spectrograph (GRIS) on 16 July 2023. We examine the coupling between the photosphere and the…

Solar and Stellar Astrophysics · Physics 2026-02-25 Z. Vashalomidze , C. Quintero Noda , T. V. Zaqarashvili , M. Benko , D. Kuridze , P. Gömöry , J. Rybák , S. Lomineishvili , M. Collados , C. Denker , M. Verma , C. Kuckein , A. Asensio Ramos

NEW INSIGHTS INTO NON-RADIATIVE HEATING IN LATE-A STAR CHROMOSPHERES

Using new and archival spectra from the Goddard High Resolution Spectrograph, we have searched for evidence of chromospheric and transition region emission in six stars of mid- to late-A spectral type. Two of the stars, alpha Aql (A7 IV-V)…

Astrophysics · Physics 2016-08-30 Frederick M. Walter , Lynn D. Matthews , Jeffrey L. Linsky

Variability of H$\alpha$ chromospheric activity of solar-like stars revealed by the time-domain data of LAMOST Medium-Resolution Spectroscopic Survey

The variability of H$\alpha$ chromospheric activity of solar-like stars is investigated by using the time-domain data of LAMOST Medium-Resolution Spectroscopic Survey (MRS). We use $R_\mathrm{H\alpha}$ index (ratio of H$\alpha$ luminosity…

Solar and Stellar Astrophysics · Physics 2025-12-10 Han He , Ali Luo , Haotong Zhang , Song Wang

Multi-wavelength analysis of high energy electrons in solar flares: a case study of August 20, 2002 flare

A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and…

Astrophysics · Physics 2008-11-26 J. Kasparova , M. Karlicky , E. P. Kontar , R. A. Schwartz , B. R. Dennis

Molecular Hydrogen Line Identifications in Solar Flares Observed by IRIS: Lower Atmospheric Structure from Radiometric Analysis

A rich spectrum of molecular hydrogen (H$_2$) emission lines is seen in sensitive observations from the far ultraviolet (FUV) channels of the Interface Region Imaging Spectrograph (IRIS) during flare activity in solar active region NOAA…

Solar and Stellar Astrophysics · Physics 2024-10-08 Sarah A. Jaeggli , Adrian N. Daw

Dark Matter Particles in the Galactic Halo

The DAMA/LIBRA-phase1 and the former DAMA/NaI data (cumulative exposure 1.33 ton $\times$ yr, corresponding to 14 annual cycles) give evidence at 9.3 $\sigma$ C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-23 R. Bernabei

Halpha line profile asymmetries and the chromospheric flare velocity field

The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Halpha and Ca II 8542 {\AA} lines are studied using…

Solar and Stellar Astrophysics · Physics 2015-11-11 D. Kuridze , M. Mathioudakis , P. J. A. Simões , L. Rouppe van der Voort , M. Carlsson , S. Jafarzadeh , J. C. Allred , A. F. Kowalski , M. Kennedy , L. Fletcher , D. Graham , F. P. Keenan

The Atmospheric Response to Large Electron Beam Fluxes in Solar Flares III: Comprehensive Modeling of the Brightest Observed Near-Ultraviolet Continuum Source in an X9 Solar Flare

I report on the high resolution spectra of the remarkable X9 solar flare of 2024 Oct 03 (SOL2024-10-03T12:08) and evaluate the extent to which nonthermal electron beams that generate dense chromospheric condensations can power very bright…

Solar and Stellar Astrophysics · Physics 2025-11-18 Adam F. Kowalski

Combined Spectroscopic and Photometric Analysis of Flares in the Dwarf M Star EV Lacertae

We report results of an observing campaign to study the dwarf M flare star EV Lacertae. Between October 2021 and January 2022 we obtained concurrent B band photometry and low resolution spectroscopy of EV Lac on 39 occasions during 10 of…

Solar and Stellar Astrophysics · Physics 2023-07-28 David Boyd , Robert Buchheim , Sean Curry , Frank Parks , Keith Shank , Forrest Sims , Gary Walker , John Wetmore , James Jackman