A Link Between White Dwarf Pulsars and Polars: Multiwavelength Observations of the 9.36-Minute Period Variable Gaia22ayj
Antonio C. Rodriguez, Kareem El-Badry, Pasi Hakala, Pablo Rodríguez-Gil, Tong Bao, Ilkham Galiullin, Jacob A. Kurlander, Casey J. Law, Ingrid Pelisoli, Matthias… 展开作者
Antonio C. Rodriguez, Kareem El-Badry, Pasi Hakala, Pablo Rodríguez-Gil, Tong Bao, Ilkham Galiullin, Jacob A. Kurlander, Casey J. Law, Ingrid Pelisoli, Matthias R. Schreiber, Kevin Burdge, Ilaria Caiazzo, Jan van Roestel, Paula Szkody, Andrew J. Drake, David A. H. Buckley, Stephen B. Potter, Boris Gaensicke, Kaya Mori, Eric C. Bellm, Shrinivas R. Kulkarni, Thomas A. Prince, Matthew Graham, Mansi M. Kasliwal, Sam Rose, Yashvi Sharma, Tomás Ahumada, Shreya Anand, Akke Viitanen, Avery Wold, Tracy X. Chen, Reed Riddle, Roger Smith
White dwarfs (WDs) are the most abundant compact objects, and recent surveys have suggested that over a third of WDs in accreting binaries host a strong (B $\gtrsim$ 1 MG) magnetic field. However, the origin and evolution of WD magnetism remain under debate. Two WD pulsars, AR Sco and J191213.72-441045.1 (J1912), have been found, which are non-accreting binaries hosting rapidly spinning (1.97-min and 5.30-min, respectively) magnetic WDs. The WD in AR Sco is slowing down on a $P/\dot{P}\approx 5.6\times 10^6$ yr timescale. It is believed they will eventually become polars, accreting systems in which a magnetic WD (B $\approx 10-240$ MG) accretes from a Roche lobe-filling donor spinning in sync with the orbit ($\gtrsim 78$ min). Here, we present multiwavelength data and analysis of Gaia22ayj, which outbursted in March 2022. We find that Gaia22ayj is a magnetic accreting WD that is rapidly spinning down ($P/\dot{P} = 6.1^{+0.3}_{-0.2}\times 10^6$ yr) like WD pulsars, but shows clear evidence of accretion, like polars. Strong linear polarization (40%) is detected in Gaia22ayj; such high levels have only been seen in the WD pulsar AR Sco and demonstrate the WD is magnetic. High speed photometry reveals a 9.36-min period accompanying a high amplitude ($\sim 2$ mag) modulation. We associate this with a WD spin or spin-orbit beat period, not an orbital period as was previously suggested. Fast (60-s) optical spectroscopy reveals a broad ``hump'', reminiscent of cyclotron emission in polars, between 4000-8000 Angstrom. We find an X-ray luminosity of $L_X = 2.7_{-0.8}^{+6.2}\times10^{32} \textrm{ erg s}^{-1}$ in the 0.3-8 keV energy range, while two VLA radio campaigns resulted in a non-detection with a $F_r < 15.8μ\textrm{Jy}$ 3$ σ$ upper limit. The shared properties of both WD pulsars and polars suggest that Gaia22ayj is a missing link between the two classes of magnetic WD binaries.
Multiwavelength search for counterparts of supersoft X-ray sources in M31
我们在哈勃空间望远镜（HST）的“全色哈勃仙女座宝库”（PHAT）档案图像和测光目录中搜索了M31中7个超软X射线源（SSS）的光学/UV/IR对应物。三个SSS是瞬态的，其他四个是持久性的来源。PHAT提供了机会，以确定SSS托管非常大的白矮星，可能爆炸的Ia型超新星在单一的简并双星，与典型的共生星，高质量的近距离双星，或系统的光度发光吸积盘的星等和颜色指数。我们发现的证据表明，瞬态SSS是经典的或经常性的新星，我们确定的两个可能的对应物可能是共生双星进行质量转移在一个非常高的速度。在其中一个持久源r3-8的误差圈内有一颗候选的吸积白矮星双星。在M31，r2-12中研究最充分的SSS的空间误差圆中，没有红巨星或AGB恒星在光学和紫外波段足够明亮，成为共生系统，承载吸积和氢燃烧的白矮星。该SSS具有周期为217.7 s的X射线通量的已知调制，并且我们测量了其导数的上限，0.82 x 10（-11）。这个极限可以与轨道周期为几小时的双星中高速吸积的白矮星的自转周期相一致。然而，没有发光的对应物具有典型的吸积盘由热的中心源照射的颜色指数。采用半经验关系，盘光学光度的上限意味着白矮星双星的轨道周期的上限只有169分钟。
Multiwavelength Imaging and Spectral Analysis of Jet-like Phenomena in a Solar Active Region Using IRIS and AIA
对动力学现象的高分辨率观测使人们能够深入了解控制太阳低层大气的性质和过程。我们提出了类似喷气现象的分析，从活动区（AR）12192半影脚点使用成像和光谱观测的界面区成像光谱仪（IRIS）和大气成像组件（AIA）上的太阳动力学天文台。这些喷流与$\pm$ 10-22 km s $^{-1}$的视线（LoS）多普勒速度和似乎以23-130 km s $^{-1}$的速度穿过天空平面（PoS）的明亮锋面有关。这样的速度比色球层中预期的声速高得多。在IRIS和AIA的冷通道和热通道中都可以看到喷流的特征。每次喷射平均持续15分钟，在2小时内发生5-7次。提出了解释这一现象的可能机制，其中最有可能的机制是由于光球波阵面或重力波的陡化而导致p模或Alfven波冲击序列撞击过渡区（TR）和日冕。
Multiwavelength observation of a large-scale flux rope eruption above kinked mini-filament
我们分析了2012年4月30日发生在AR NOAA 111465的西临耀斑（C3.9）的多波长观测。SDO/AIA 304、1600射电望远镜和Hinode/SOT H $α$记录的高分辨率图像显示了一个与扭结不稳定性相关的小暗条（上升速度$\sim$ 40 km s $^{-1}$）的激活和暗条南支附近C级耀斑的开始。第一次磁重联发生在暗条的一个足点，导致其南支断裂。花丝显示北支和顶点逆时针方向的解绕运动，未能爆发。磁通绳（仅在热通道中可见，即，AIA 131和94通道和Hinode/SXT）结构在扭结丝上发生第二次磁重联时沿中性线出现。在扭曲的暗条上方形成RHESSI硬X射线源（12-25 keV），同时出现与光球增亮（AIA 1700 <$）相关的131 <$s热环，表明粒子从暗条顶部沿着这些环加速。此外，在171光年的灯丝上方观察到的EUV扰动/波也显示出与磁重联的密切联系。磁通绳慢慢上升（$\sim$ 100 km s $^{-1}$）可能通过在$\sim$ 15-20分钟内与周围剪切磁场重联而产生相当大的扭曲结构，AIA 171和SWAP 174的图像显示了一个冷压缩锋，（或CME锋面环）周围的热通量绳结构。
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. III. Comparison between Starspot Mapping, Zeeman Doppler Imaging, and Multiwavelength Variability
Hitotsubashi University（一桥大学）；The University of Tokyo（东京大学）；The Hakubi Center for Advanced Research, Kyoto University（京都大学博雅研究高级中心）；Department of Physics, Kyoto University（京都大学物理学系）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Department of Physics, The Catholic University of America（美利坚天主教大学物理学系）；Division of Science, National Astronomical Observatory of Japan, NINS（日本国立天文台科学部）；Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES（图卢兹大学、法国国家科学研究中心、法国国家空间研究中心天体物理与行星学研究所在）；Department of Physics, American University（美国大学物理学系）
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. II. Understanding Prominence Eruption through Data-Driven Modeling and Observed Magnetic Environment
Comparison of multiwavelength observations of 9 broad-band pulsars with the spectrum of the emission from an extended current with a superluminally rotating distribution pattern
Simultaneous Multiwavelength Observations of Magnetic Activity in Ultracool Dwarfs. IV. The Active, Young Binary NLTT 33370 AB (=2MASS J13142039+1320011)
Multiwavelength Observations of the Precursors Before the Eruptive X4.9 Limb Solar Flare on 25 February, 2014: Current Sheet, Eruptive Filament, Flare and Eruption Onset in the Frame of the Tether-Cutting Magnetic Reconnection Scenario
V844 Herculis: An Exceptional Intermediate Polar Hiding in an Ordinary Dwarf Nova
University of Notre Dame（圣母大学）；University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Bay Area Environmental Research Institute（湾区环境研究所）；University College Cork（科克大学学院）；The University of Manchester（曼彻斯特大学）；University of Washington（华盛顿大学）；University of Virginia（弗吉尼亚大学）；Observatorio Astronómico “Las Pegueras”（拉斯佩格拉斯天文台）；Warren Williams College（沃伦威廉姆斯学院）；AAVSO（美国变星观测者协会）
