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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3821 results found.

  1. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  2. GRB240529A: BOOTES-6/DPRT optical detection
  3. GRB 240529A: NOT optical observations
  4. GRB 240529A: AstroSat CZTI detection
  5. Swift GRB240529.12: Global MASTER-Net observations report
  6. Fermi GRB 240527A: Global MASTER-Net observations report
  7. LAT GRB240527.59: Global MASTER-Net observations report
  8. Fermi trigger No 738348224: Global MASTER-Net observations report
  9. Fermi trigger No 738330463: Global MASTER-Net observations report
  10. Fermi trigger No 737996942: Global MASTER-Net observations report
  11. GRB 240516B: AstroSat CZTI detection
  12. GRB 240516A: Swift-BAT refined analysis
  13. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  14. GRB 240516A: GOTO optical upper limit
  15. GRB 240516A: Swift detection of a burst
  16. Fermi GRB 240514B: Global MASTER-Net observations report
  17. LAT GRB240513.31: Global MASTER-Net observations report
  18. Fermi GRB 240513B: Global MASTER-Net observations report
  19. Fermi trigger No 737277727: Global MASTER-Net observations report
  20. Fermi trigger No 737247400: Global MASTER-Net observations report
  21. Fermi trigger No 737168073: Global MASTER-Net observations report
  22. Fermi trigger No 737173236: Global MASTER-Net observations report
  23. Fermi trigger No 737105243: Global MASTER-Net observations report
  24. Fermi trigger No 737152719: Global MASTER-Net observations report
  25. Fermi trigger No 737111207: Global MASTER-Net observations report
  26. EP240506a: CrAO ZTSH optical upper limit
  27. EP240506a: Optical upper limit with Kinder observations
  28. IPN triangulation of GRB 240504A
  29. GRB 240502A: 1.3m DFOT Optical upper limit
  30. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  31. GRB 240415A 1.3m DFOT Optical upper limit
  32. Fermi GRB 240502B: Global MASTER-Net observations report
  33. Fermi GRB 240502A: Global MASTER-Net observations report
  34. Fermi trigger No 736197684: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
  36. GRB 240429A: Fermi GBM Final Real-time Localization
  37. LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  39. LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
  40. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  41. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  42. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  43. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  44. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  45. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  46. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  47. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  48. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  49. Fermi trigger No 735470374: Global MASTER-Net observations report
  50. Fermi GRB 240421B: Global MASTER-Net observations report
  51. GRB 240421B: Fermi GBM Observation
  52. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  53. Fermi trigger No 735280430: Global MASTER-Net observations report
  54. GRB 240411A: GOTO early optical upper limits
  55. Fermi GRB 240417A: Global MASTER-Net observations report
  56. Fermi GRB 240415A: Global MASTER-Net observations report
  57. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  58. IPN triangulation of GRB 240410A
  59. IPN triangulation of GRB 240411A
  60. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  61. Fermi GRB 240407A: Global MASTER-Net observations report
  62. GRB 240402C: Glowbug gamma-ray detection
  63. GRB 240402C: GRBAlpha detection
  64. Fermi GRB 240402A: Global MASTER-Net observations report
  65. GRB 240329A: Glowbug gamma-ray detection
  66. GRB 240329A: AstroSat CZTI detection
  67. GRB 240329A: GRBAlpha detection
  68. Fermi trigger No 733366352: Global MASTER-Net observations report
  69. Fermi GRB 240329A: Global MASTER-Net observations report
  70. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  71. GRB 240329A: Fermi GBM Final Real-time Localization
  72. Fermi GRB 240328B: Global MASTER-Net observations report
  73. Fermi GRB 240328A: Global MASTER-Net observations report
  74. GRB 240320A: Glowbug gamma-ray detection
  75. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  76. Fermi trigger No 732657380: Global MASTER-Net observations report
  77. GRB 240320A: Fermi GBM Final Real-time Localization
  78. Fermi GRB 240318A: Global MASTER-Net observations report
  79. Fermi GRB 240317B: Global MASTER-Net observations report
  80. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  81. Fermi trigger No 732299243: Global MASTER-Net observations report
  82. GRB 240315A: Fermi GBM Final Real-time Localization
  83. Fermi trigger No 731839490: Global MASTER-Net observations report
  84. Fermi GRB 240310A: Global MASTER-Net observations report
  85. GRB 240309A: MAXI/GSC detection
  86. GRID detection of GRB 240229A (Updated Report)
  87. GRID detection of GRB 240229A
  88. GRB 240229A: Glowbug gamma-ray detection
  89. GRB 240229A: GRBAlpha detection
  90. Fermi-LAT gamma-ray observations of IceCube-240229A
  91. GRB 240305C: AstroSat CZTI detection of a short burst
  92. GRB 240229A: VZLUSAT-2 detection
  93. Fermi trigger No 731161136: Global MASTER-Net observations report
  94. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 240229A: CALET Gamma-Ray Burst Monitor detection
  96. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  97. GRB 240225B: further SAO RAS optical observations
  98. Fermi GRB 240229A: Global MASTER-Net observations report
  99. IceCube Alert 240229.66: Global MASTER-Net observations report
  100. GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)

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