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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"

3136 results found.

  1. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  2. Fermi trigger No 740166710: Global MASTER-Net observations report
  3. Fermi GRB 240611A: Global MASTER-Net observations report
  4. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  5. GRB 240607A: AstroSat CZTI detection of bright long burst
  6. Fermi trigger No 739373591: Global MASTER-Net observations report
  7. Fermi GRB 240604A: Global MASTER-Net observations report
  8. Fermi GRB 240605A: Global MASTER-Net observations report
  9. Fermi GRB 240603C: Global MASTER-Net observations report
  10. Fermi GRB 240602A: Global MASTER-Net observations report
  11. GRB 240531A: AstroSat CZTI detection of a short burst
  12. GRB 240529A: J-band detections with WINTER
  13. GRB 240529A: Skynet Optical Observations
  14. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  15. GRB 240529A: AstroSat CZTI detection
  16. LAT GRB240527.59: Global MASTER-Net observations report
  17. Fermi GRB 240527B: Global MASTER-Net observations report
  18. Fermi trigger No 738348224: Global MASTER-Net observations report
  19. Fermi trigger No 737996942: Global MASTER-Net observations report
  20. GRB 240516B: AstroSat CZTI detection
  21. GRB 240519A: AstroSat CZTI detection
  22. Fermi GRB 240517A: Global MASTER-Net observations report
  23. GRB 240516A: AstroSat CZTI detection
  24. MAXI GRB240514.78: Global MASTER-Net observations report
  25. GRB 240514D: AstroSat CZTI detection
  26. Fermi GRB 240514B: Global MASTER-Net observations report
  27. LAT GRB240513.31: Global MASTER-Net observations report
  28. Fermi trigger No 737277727: Global MASTER-Net observations report
  29. GRB 240513B: Fermi GBM Final Real-time Localization
  30. GRB 240513A: AstroSat CZTI detection
  31. Fermi trigger No 737168073: Global MASTER-Net observations report
  32. Fermi trigger No 737152719: Global MASTER-Net observations report
  33. Fermi trigger No 736733320: Global MASTER-Net observations report
  34. Fermi trigger No 736564880: Global MASTER-Net observations report
  35. GRB 240503A: AstroSat CZTI detection
  36. Fermi trigger No 736387941: Global MASTER-Net observations report
  37. Fermi trigger No 736379109: Global MASTER-Net observations report
  38. Fermi GRB 240502A: Global MASTER-Net observations report
  39. GRB 240502B: Fermi GBM Final Real-time Localization
  40. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  41. Fermi trigger No 736197684: Global MASTER-Net observations report
  42. GRB 240501B: AstroSat CZTI detection
  43. GRB 240408B: VZLUSAT-2 detection
  44. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  45. GRB 240426A: AstroSat CZTI detection
  46. EP240426a: YAHPT optical upper limit
  47. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  48. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  49. GRB 240425A: Fermi GBM Final Real-time Localization
  50. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  51. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  52. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  53. GRB 240421B: GRBAlpha detection
  54. LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
  55. GRB 240419A: Possible ATCA radio detection
  56. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  57. GRB 240414A: radio detection with the VLA
  58. GRB 240421B: AstroSat CZTI detection
  59. GRB240421B: Zadko Observations
  60. Fermi GRB 240421B: Global MASTER-Net observations report
  61. Swift GRB 240421B: Global MASTER-Net observations report
  62. GRB 240421B: Fermi GBM Observation
  63. GRB 240421B: Swift-XRT refined Analysis
  64. GRB 240421B: Swift detection of a burst
  65. Fermi trigger No 735280430: Global MASTER-Net observations report
  66. IceCube Alert 240419.98: Global MASTER-Net observations report
  67. GRB 240419A: VLT/UVES redshift of z = 5.178
  68. EP240414a: GMG observation
  69. GRB 240418A: AKO Upper Limit
  70. Fermi GRB 240417A: Global MASTER-Net observations report
  71. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  72. GRB 240417A: Fermi GBM Final Real-time Localization
  73. EP240416A: MASTER optical observations
  74. EP240416a: EP-WXT detection of a fast X-ray transient
  75. Fermi GRB 240415A: Global MASTER-Net observations report
  76. GRB 240414A: Photometric observation from 2.2m CAHA
  77. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 240415A: Fermi GBM Final Real-time Localization
  79. EP240413A: GOTO optical upper limits
  80. Fermi trigger No 734754044: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  82. GRB 240408B: AstroSat CZTI detection
  83. Fermi GRB 240407A: Global MASTER-Net observations report
  84. LXT 240402A: MASTER optical observations with AGN in error-box
  85. Fermi GRB 240402A: Global MASTER-Net observations report
  86. GRB 240329A: Glowbug gamma-ray detection
  87. GRB 240324A: AstroSat CZTI detection of a short burst
  88. GRB 240331A: AstroSat CZTI detection
  89. GRB 240329A: AstroSat CZTI detection
  90. Fermi trigger No 733366352: Global MASTER-Net observations report
  91. Fermi trigger No 732937833: Global MASTER-Net observations report
  92. Fermi GRB 240320A: Global MASTER-Net observations report
  93. X-ray transient EP 240315a: Chandra observations
  94. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  95. GRB 240317A: AstroSat CZTI detection
  96. GRB 240315B: AstroSat CZTI detection
  97. Fermi GRB 240317B: Global MASTER-Net observations report
  98. Fermi trigger No 732299243: Global MASTER-Net observations report
  99. Fermi GRB 240314A: Global MASTER-Net observations report
  100. Fermi trigger No 731839490: Global MASTER-Net observations report

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