Long Period radio Transients (LPTs) are a mysterious new class of radio transients pulsating on periods of minutes to hours. So far, eight LPTs have been discovered predominantly at low Galactic latitudes, yet their nature remains unknown. Here, I present the first phase-resolved optical spectroscopy of the 2.9-h LPT GLEAM-X J0704-37, acquired with the 10-m Keck I telescope. Radial velocity (RV) shifts of $189\pm 3 \textrm{km s}^{-1}$ of an M5-type star in a binary system are detected on a period nearly equal to the radio period. Weak H$α$ emission is also present, with some of it possibly originating from outside of the M dwarf. Based on the RV amplitude, and assuming a typical M dwarf mass, the companion mass must be $M \geq 0.22 M_\odot$. Calibrating the spectra with space-based \textit{Gaia} photometry reveals that the system is nearly four times closer than previously reported, at $d \approx 400$ pc, suggesting that more systems could be nearby and amenable to optical characterization. The optical spectrum between 3500-10,000 Angstrom is well modeled by a binary comprised of a massive white dwarf (WD; $T_\textrm{eff}\approx$7,300 K, $M\approx0.8-1.0M_\odot$) and M dwarf ($T_\textrm{eff}\approx$3,000 K, $M\approx0.14M_\odot$). Radio pulses arrive when the WD is at nearly maximum blueshift and the M dwarf at nearly maximum redshift, in contrast to what has been reported in a similar LPT, ILT J1101+5521. GLEAM-X J0704-37 is now the second LPT with an orbital period nearly equal to the radio period, hinting at two classes of LPTs: ``long LPTs'' ($P\gtrsim$78 min) associated with WD + M dwarf binary orbits, and ``short LPTs'' ($P\lesssim$78 min) related to WD or neutron star spins. This work demonstrates that precise localization of LPTs, which enables optical follow-up, will be key in uncovering the mechanism(s) that power this new class of phenomenon.
The Zwicky Transient Facility Census of the Local Universe I: Systematic search for Calcium rich gap transients reveal three related spectroscopic sub-classes
Spectroscopic and imaging observations of transient hot and cool loops by IRIS and SDO
日冕环是太阳大气的基本组成部分，可以在各种长度尺度上观测到。但其形成机制尚不清楚。在本文中，我们提出的光谱和成像观测的小尺度瞬变和随后形成的瞬态循环。为此，我们利用了AIA和IRIS-SJI记录的多波长观测，以及IRIS提供的光谱测量。对于光球磁场数据，我们获得了HMI提供的视线磁图数据。同时观察到小规模的瞬态与几个EUV和UV通带的AIA和IRIS-SJI。HMI磁图提供了这些瞬变下负通量抵消的证据。差分发射测量（DEM）分析表明，瞬态达到的温度高达8 MK，而另一个只达到0.4 MK。这些瞬态进一步导致形成具有相似温度分布的小尺度回路，因此分别称为热回路和冷回路。在事件发生的过程中，IRIS狭缝对该区域进行光栅扫描，从而提供了瞬态和相关环路的光谱测量。这使我们能够对热回路和冷回路进行深入研究。利用密度敏感的O-IV线对，我们得到了沿热环和冷环的平均电子密度分别为$10^{11.2}$和$10^{10.8}$ cm $^{-3}$。能量估计表明，磁通抵消可以很容易地为热瞬态供电，而不足以为冷瞬态供电。寿命估计和磁场外推表明存在小规模和精细结构内这些循环。结果提供了至关重要的成分的物理回路的形成和相关的热力学。
The benefit of a multi-band high resolution spectroscopic monitoring for studying stellar transients: the NGC 300 OT2008-1 UVES spectrum as a test case
INAF-OATS（意大利国家天体物理研究所奥斯塔天文台）；Dipartimento di Fisica “Enrico Fermi”, Università di Pisa（比萨大学费米物理系）；INAF-OAPD（意大利国家天体物理研究所帕多瓦天文台）
Supernovae Shock Breakout/Emergence Detection Predictions for a Wide-Field X-ray Survey
目前有许多大型实地调查正在运作和计划中，包括强大的Vera C。Rubin Observatory Legacy Survey of Space and Time的照片这些调查将大大增加瞬态的数量和多样性。然而，对于某些瞬变现象，如超新星（SNe），我们可以通过定向观测（如激波爆发，$γ$射线探测）而不是简单地增加样本量来获得更多的理解。例如，这些瞬态的初始发射可以是这些爆炸的有力探测器。即将到来的地面探测器并不理想地适合于观测这些瞬变的初始发射（冲击波出现）。这些观测需要一个大视场的X射线任务，并在激波爆发的第一个小时内进行紫外线跟踪。在最初的一小时甚至一天内的辐射对恒星半径和恒星外层的不对称性、星周介质的性质（例如，核塌缩SNe风的不均匀性、热核SNe中的吸积伴星）以及这两者之间的过渡区提供了强有力的约束。本文对大视场龙虾眼X射线和紫外天文台所能观测到的超新星的数量进行了模拟。
Long Period Transients (LPTs): a comprehensive review
Institute of Space Sciences (ICE), CSIC（空间科学研究所）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚太空研究学院）；International Centre for Radio Astronomy Research, Curtin University（西澳大学国际射电天文研究中心）；Sydney Institute for Astronomy, School of Physics, The University of Sydney（悉尼大学物理学院天体物理学研究所）；ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav)（引力波发现卓越中心）
Time resolved spectroscopy and photometry of three little known bright cataclysmic variables: LS IV -08$^{\rm o}$ 3, HQ Monocerotis and ST Chamaeleontis
Anomaly Hunter for Alerts (AHA): Anomaly Detection in the ZTF Transient Alert Stream
Breakthrough Listen, Department of Physics, University of Oxford（牛津大学物理系突破聆听项目）；Department of Physics, University of Oxford（牛津大学物理系）；SETI Institute（SETI研究所）；Berkeley SETI Research Center, University of California, Berkeley（加州大学伯克利分校伯克利SETI研究中心）；Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast（贝尔法斯特女王大学数学与物理学院天体物理研究中心）
Investigating Pre-flare Signatures in Spectroscopic Observations of an X9-class Solar Flare
New Jersey Institute of Technology（新泽西理工学院）；Observatoire de Paris, Université PSL, CNRS, Sorbonne Université（巴黎天文台，巴黎文理研究大学，法国国家科学研究中心，索邦大学）；National Solar Observatory（美国国家太阳天文台）；University of Colorado Boulder（科罗拉多大学博尔德分校）
