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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

23717 results found.

  1. GRB 240419B : MITSuME Akeno optical upper limits
  2. GRB 240415B: Swift-XRT observations
  3. Fermi GRB 240422A: Global MASTER-Net observations report
  4. Fermi GRB 240421B: Global MASTER-Net observations report
  5. Swift GRB 240421B: Global MASTER-Net observations report
  6. GRB 240421B: Fermi GBM Observation
  7. GRB 240421B: Swift-XRT refined Analysis
  8. GRB240421B: BOOTES-5/JGT optical upper limit
  9. GRB 240421B: Swift/UVOT Upper Limits
  10. Fermi GRB 240421A: Global MASTER-Net observations report
  11. EP240420a: Xinglong decaying optical counterpart
  12. GRB 240421B: Swift detection of a burst
  13. EP240420a: Nanshan optical counterpart observations
  14. EP240420a: GWAC-F50A optical upper limit
  15. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  16. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  17. EP240420a: NOT optical counterpart candidate and potential host
  18. Fermi trigger No 735280430: Global MASTER-Net observations report
  19. IceCube Alert 240419.98: Global MASTER-Net observations report
  20. GRB 240419B: Swift/UVOT Upper Limits
  21. EP240420a: EP-WXT detection of a fast X-ray transient
  22. GRB 240419A: Swift/UVOT Upper Limits
  23. GRB 240419B: Swift-XRT refined Analysis
  24. Swift GRB 240419B: Global MASTER-Net observations report
  25. Swift GRB 240419A: Global MASTER-Net observations report
  26. GRB 240418A: Swift/UVOT Upper Limits
  27. GRB 240419A: REM NIR afterglow detection
  28. GRB 240419A: Swift-XRT refined Analysis
  29. GRB 240418A: Swift-XRT refined Analysis
  30. GRB 240419B: Swift detection of a burst
  31. GRB 240411B: Swift/UVOT Detection
  32. Fermi trigger No 735089036: Global MASTER-Net observations report
  33. EP240416a: J-band observations with WINTER
  34. EP240414a: GMG observation
  35. GRB 240419A: Swift detection of a burst
  36. GRB 240411A: GOTO early optical upper limits
  37. Swift GRB240418.85: Global MASTER-Net observations report
  38. GRB 240418A: Swift detection of a burst
  39. EP240417a: EP-WXT detection of a fast X-ray transient
  40. Fermi GRB 240417A: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  42. Improved IPN triangulation of GRB 240411A
  43. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  44. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  45. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  46. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  47. GRB 240415A: Glowbug gamma-ray detection
  48. GRB 240414A: Glowbug gamma-ray detection
  49. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  50. EP 240416a: Xinglong and NOT decaying optical counterpart
  51. GRB 240415A: Swift-BAT refined analysis
  52. EP240416A: MASTER optical observations
  53. GRB 240411A: Glowbug gamma-ray detection
  54. GRB 240414A: Swift-BAT refined analysis
  55. EP240416a: Kinder optical counterpart candidate
  56. EP240416a: EP-WXT detection of a fast X-ray transient
  57. GRB 240415A: Swift/UVOT Detection
  58. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  59. GRB 240415A: Earliest optical followup with the Kinder observations
  60. GRB 240414A: GMG observation
  61. EP 240414a: BOOTES-4/MET Optical Upper Limits
  62. EP240414a: EP-FXT follow-up observation
  63. GRB 240415A: OHP/T193 optical observations
  64. GRB 240415A: SAO RAS optical observations
  65. Fermi GRB 240415A: Global MASTER-Net observations report
  66. GRB 240414A: Swift/UVOT Detection
  67. GRB 240415A: Prompt Swift-XRT observations
  68. GRB 240415A: Swift detection of a burst
  69. EP240413a: Upper limits from GECAM-B Observation
  70. EP 240414a: NOT optical counterpart confirmation
  71. GRB 240414A: Swift-XRT refined Analysis
  72. GRB240414A : J-band upper limits from WINTER
  73. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  74. EP240413A: GOTO optical upper limits
  75. Fermi trigger No 734754044: Global MASTER-Net observations report
  76. Swift GRB 240414A: Global MASTER-Net observations report
  77. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  78. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  79. EP240414a: EP-WXT detection of a fast X-ray transient
  80. IPN triangulation of GRB 240411A
  81. GRB 240414A : MITSuME Akeno optical upper limits
  82. EP240413a: EP-WXT detection of a fast X-ray transient
  83. GRB 240414A: Swift detection of a burst
  84. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  85. EP240408a: GSP optical upper limit
  86. GRB 240411B: Kinder observations with Lulin observatory
  87. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  88. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  89. IceCube Alert 240412.23: Global MASTER-Net observations report
  90. GRB 240411B: Swift-BAT refined analysis
  91. GRB 240411A: GRBAlpha detection
  92. GRB 240405A: Glowbug gamma-ray detection
  93. GRB 240411B: LCO optical afterglow detection
  94. GRB 240411B: Swift detection of a burst
  95. GRB 240408B: GRBAlpha detection
  96. EP240408A: MASTER optical observations
  97. EP240408a: Upper limits from GECAM-B Observation
  98. EP240408a: Swift follow-up observation
  99. EP240408a: BOOTES-6/DPRT optical upper limit
  100. GRB 240405A: GRBAlpha detection

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