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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').

3410 results found.

  1. GRB 240516A: Swift-BAT refined analysis
  2. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  3. GRB 240516A: GOTO optical upper limit
  4. GRB 240516A: Swift detection of a burst
  5. Fermi GRB 240514B: Global MASTER-Net observations report
  6. LAT GRB240513.31: Global MASTER-Net observations report
  7. Fermi GRB 240513B: Global MASTER-Net observations report
  8. Fermi trigger No 737277727: Global MASTER-Net observations report
  9. Fermi trigger No 737247400: Global MASTER-Net observations report
  10. Fermi trigger No 737168073: Global MASTER-Net observations report
  11. Fermi trigger No 737173236: Global MASTER-Net observations report
  12. Fermi trigger No 737105243: Global MASTER-Net observations report
  13. Fermi trigger No 737152719: Global MASTER-Net observations report
  14. Fermi trigger No 737111207: Global MASTER-Net observations report
  15. EP240506a: CrAO ZTSH optical upper limit
  16. EP240506a: Optical upper limit with Kinder observations
  17. IPN triangulation of GRB 240504A
  18. GRB 240502A: 1.3m DFOT Optical upper limit
  19. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  20. GRB 240415A 1.3m DFOT Optical upper limit
  21. Fermi GRB 240502B: Global MASTER-Net observations report
  22. Fermi GRB 240502A: Global MASTER-Net observations report
  23. Fermi trigger No 736197684: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  25. GRB 240429A: Fermi GBM Final Real-time Localization
  26. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  28. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  29. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  30. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  31. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  32. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  33. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  34. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  35. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  36. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  37. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  38. Fermi trigger No 735470374: Global MASTER-Net observations report
  39. Fermi GRB 240421B: Global MASTER-Net observations report
  40. GRB 240421B: Fermi GBM Observation
  41. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  42. Fermi trigger No 735280430: Global MASTER-Net observations report
  43. GRB 240411A: GOTO early optical upper limits
  44. Fermi GRB 240417A: Global MASTER-Net observations report
  45. Fermi GRB 240415A: Global MASTER-Net observations report
  46. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  47. IPN triangulation of GRB 240410A
  48. IPN triangulation of GRB 240411A
  49. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  50. Fermi GRB 240407A: Global MASTER-Net observations report
  51. GRB 240402C: Glowbug gamma-ray detection
  52. GRB 240402C: GRBAlpha detection
  53. Fermi GRB 240402A: Global MASTER-Net observations report
  54. GRB 240329A: Glowbug gamma-ray detection
  55. GRB 240329A: AstroSat CZTI detection
  56. GRB 240329A: GRBAlpha detection
  57. Fermi trigger No 733366352: Global MASTER-Net observations report
  58. Fermi GRB 240329A: Global MASTER-Net observations report
  59. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  60. GRB 240329A: Fermi GBM Final Real-time Localization
  61. Fermi GRB 240328B: Global MASTER-Net observations report
  62. Fermi GRB 240328A: Global MASTER-Net observations report
  63. GRB 240320A: Glowbug gamma-ray detection
  64. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  65. Fermi trigger No 732657380: Global MASTER-Net observations report
  66. GRB 240320A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 240318A: Global MASTER-Net observations report
  68. Fermi GRB 240317B: Global MASTER-Net observations report
  69. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  70. Fermi trigger No 732299243: Global MASTER-Net observations report
  71. GRB 240315A: Fermi GBM Final Real-time Localization
  72. Fermi trigger No 731839490: Global MASTER-Net observations report
  73. Fermi GRB 240310A: Global MASTER-Net observations report
  74. GRB 240309A: MAXI/GSC detection
  75. GRID detection of GRB 240229A (Updated Report)
  76. GRID detection of GRB 240229A
  77. GRB 240229A: Glowbug gamma-ray detection
  78. GRB 240229A: GRBAlpha detection
  79. Fermi-LAT gamma-ray observations of IceCube-240229A
  80. GRB 240305C: AstroSat CZTI detection of a short burst
  81. GRB 240229A: VZLUSAT-2 detection
  82. Fermi trigger No 731161136: Global MASTER-Net observations report
  83. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 240229A: CALET Gamma-Ray Burst Monitor detection
  85. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 240225B: further SAO RAS optical observations
  87. Fermi GRB 240229A: Global MASTER-Net observations report
  88. IceCube Alert 240229.66: Global MASTER-Net observations report
  89. GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
  90. GRB 240229A: Fermi GBM Final Real-time Localization
  91. GRB 240225B: VLT/X-shooter redshift
  92. GRB 240225B: 3.6m DOT observation
  93. GRB 240225B: MAXI/GSC detection
  94. Transient EPW20240219aa: Mondy optical observations
  95. Fermi trigger No 729914426: Global MASTER-Net observations report
  96. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  97. Fermi trigger No 729650855: Global MASTER-Net observations report
  98. Fermi GRB 240213A: Global MASTER-Net observations report
  99. Fermi trigger No 729152364: Global MASTER-Net observations report
  100. Fermi trigger No 729012023: Global MASTER-Net observations report

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