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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"

2853 results found.

  1. GRB 240713B: AstroSat CZTI detection of a long burst
  2. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  4. EP240703a: Kinder optical follow-up observations
  5. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  6. Fermi GRB 240702A: Global MASTER-Net observations report
  7. Fermi trigger No 741448122: Global MASTER-Net observations report
  8. GRB 240629A: Fermi GBM Final Real-time Localization
  9. Fermi trigger No 741296200: Global MASTER-Net observations report
  10. GRB 240627A: AstroSat CZTI detection
  11. EP240625a: GRANDMA Optical Upper Limits
  12. EP240625a: NOT optical counterpart candidate
  13. Fermi trigger No 740949590: Global MASTER-Net observations report
  14. IPN triangulation of GRB 240615A (short)
  15. GRB 240619C: AstroSat CZTI detection
  16. Fermi trigger No 740474239: Global MASTER-Net observations report
  17. Fermi trigger No 740430582: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  19. Fermi trigger No 740166710: Global MASTER-Net observations report
  20. Fermi GRB 240611A: Global MASTER-Net observations report
  21. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  22. GRB 240607A: AstroSat CZTI detection of bright long burst
  23. Fermi trigger No 739373591: Global MASTER-Net observations report
  24. Fermi GRB 240604A: Global MASTER-Net observations report
  25. Fermi GRB 240605A: Global MASTER-Net observations report
  26. Fermi GRB 240603C: Global MASTER-Net observations report
  27. Fermi GRB 240602A: Global MASTER-Net observations report
  28. GRB 240531A: AstroSat CZTI detection of a short burst
  29. GRB 240529A: J-band detections with WINTER
  30. GRB 240529A: Skynet Optical Observations
  31. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  32. GRB 240529A: AstroSat CZTI detection
  33. LAT GRB240527.59: Global MASTER-Net observations report
  34. Fermi GRB 240527B: Global MASTER-Net observations report
  35. Fermi trigger No 738348224: Global MASTER-Net observations report
  36. Fermi trigger No 737996942: Global MASTER-Net observations report
  37. GRB 240516B: AstroSat CZTI detection
  38. GRB 240519A: AstroSat CZTI detection
  39. Fermi GRB 240517A: Global MASTER-Net observations report
  40. GRB 240516A: AstroSat CZTI detection
  41. MAXI GRB240514.78: Global MASTER-Net observations report
  42. GRB 240514D: AstroSat CZTI detection
  43. Fermi GRB 240514B: Global MASTER-Net observations report
  44. LAT GRB240513.31: Global MASTER-Net observations report
  45. Fermi trigger No 737277727: Global MASTER-Net observations report
  46. GRB 240513B: Fermi GBM Final Real-time Localization
  47. GRB 240513A: AstroSat CZTI detection
  48. Fermi trigger No 737168073: Global MASTER-Net observations report
  49. Fermi trigger No 737152719: Global MASTER-Net observations report
  50. Fermi trigger No 736733320: Global MASTER-Net observations report
  51. Fermi trigger No 736564880: Global MASTER-Net observations report
  52. GRB 240503A: AstroSat CZTI detection
  53. Fermi trigger No 736387941: Global MASTER-Net observations report
  54. Fermi trigger No 736379109: Global MASTER-Net observations report
  55. Fermi GRB 240502A: Global MASTER-Net observations report
  56. GRB 240502B: Fermi GBM Final Real-time Localization
  57. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  58. Fermi trigger No 736197684: Global MASTER-Net observations report
  59. GRB 240501B: AstroSat CZTI detection
  60. GRB 240408B: VZLUSAT-2 detection
  61. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  62. GRB 240426A: AstroSat CZTI detection
  63. EP240426a: YAHPT optical upper limit
  64. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  65. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  66. GRB 240425A: Fermi GBM Final Real-time Localization
  67. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  68. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  69. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  70. GRB 240421B: GRBAlpha detection
  71. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  72. GRB 240419A: Possible ATCA radio detection
  73. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  74. GRB 240414A: radio detection with the VLA
  75. GRB 240421B: AstroSat CZTI detection
  76. GRB240421B: Zadko Observations
  77. Fermi GRB 240421B: Global MASTER-Net observations report
  78. Swift GRB 240421B: Global MASTER-Net observations report
  79. GRB 240421B: Fermi GBM Observation
  80. GRB 240421B: Swift-XRT refined Analysis
  81. GRB 240421B: Swift detection of a burst
  82. Fermi trigger No 735280430: Global MASTER-Net observations report
  83. IceCube Alert 240419.98: Global MASTER-Net observations report
  84. GRB 240419A: VLT/UVES redshift of z = 5.178
  85. EP240414a: GMG observation
  86. GRB 240418A: AKO Upper Limit
  87. Fermi GRB 240417A: Global MASTER-Net observations report
  88. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  89. GRB 240417A: Fermi GBM Final Real-time Localization
  90. EP240416A: MASTER optical observations
  91. EP240416a: EP-WXT detection of a fast X-ray transient
  92. Fermi GRB 240415A: Global MASTER-Net observations report
  93. GRB 240414A: Photometric observation from 2.2m CAHA
  94. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 240415A: Fermi GBM Final Real-time Localization
  96. EP240413A: GOTO optical upper limits
  97. Fermi trigger No 734754044: Global MASTER-Net observations report
  98. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  99. GRB 240408B: AstroSat CZTI detection
  100. Fermi GRB 240407A: Global MASTER-Net observations report

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