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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"

23727 results found.

  1. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  2. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  3. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  4. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  6. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  7. Fermi trigger No 735470374: Global MASTER-Net observations report
  8. GRB 240421A: Glowbug gamma-ray detection
  9. GRB 240414A: radio detection with the VLA
  10. GRB 240414A: LBT optical detection
  11. GRB 240419B : MITSuME Akeno optical upper limits
  12. GRB 240415B: Swift-XRT observations
  13. Fermi GRB 240422A: Global MASTER-Net observations report
  14. Fermi GRB 240421B: Global MASTER-Net observations report
  15. Swift GRB 240421B: Global MASTER-Net observations report
  16. GRB 240421B: Fermi GBM Observation
  17. GRB 240421B: Swift-XRT refined Analysis
  18. GRB240421B: BOOTES-5/JGT optical upper limit
  19. GRB 240421B: Swift/UVOT Upper Limits
  20. Fermi GRB 240421A: Global MASTER-Net observations report
  21. EP240420a: Xinglong decaying optical counterpart
  22. GRB 240421B: Swift detection of a burst
  23. EP240420a: Nanshan optical counterpart observations
  24. EP240420a: GWAC-F50A optical upper limit
  25. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  26. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  27. EP240420a: NOT optical counterpart candidate and potential host
  28. Fermi trigger No 735280430: Global MASTER-Net observations report
  29. IceCube Alert 240419.98: Global MASTER-Net observations report
  30. GRB 240419B: Swift/UVOT Upper Limits
  31. EP240420a: EP-WXT detection of a fast X-ray transient
  32. GRB 240419A: Swift/UVOT Upper Limits
  33. GRB 240419B: Swift-XRT refined Analysis
  34. Swift GRB 240419B: Global MASTER-Net observations report
  35. Swift GRB 240419A: Global MASTER-Net observations report
  36. GRB 240418A: Swift/UVOT Upper Limits
  37. GRB 240419A: REM NIR afterglow detection
  38. GRB 240419A: Swift-XRT refined Analysis
  39. GRB 240418A: Swift-XRT refined Analysis
  40. GRB 240419B: Swift detection of a burst
  41. GRB 240411B: Swift/UVOT Detection
  42. Fermi trigger No 735089036: Global MASTER-Net observations report
  43. EP240416a: J-band observations with WINTER
  44. EP240414a: GMG observation
  45. GRB 240419A: Swift detection of a burst
  46. GRB 240411A: GOTO early optical upper limits
  47. Swift GRB240418.85: Global MASTER-Net observations report
  48. GRB 240418A: Swift detection of a burst
  49. EP240417a: EP-WXT detection of a fast X-ray transient
  50. Fermi GRB 240417A: Global MASTER-Net observations report
  51. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  52. Improved IPN triangulation of GRB 240411A
  53. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  54. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  55. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  56. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  57. GRB 240415A: Glowbug gamma-ray detection
  58. GRB 240414A: Glowbug gamma-ray detection
  59. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  60. EP 240416a: Xinglong and NOT decaying optical counterpart
  61. GRB 240415A: Swift-BAT refined analysis
  62. EP240416A: MASTER optical observations
  63. GRB 240411A: Glowbug gamma-ray detection
  64. GRB 240414A: Swift-BAT refined analysis
  65. EP240416a: Kinder optical counterpart candidate
  66. EP240416a: EP-WXT detection of a fast X-ray transient
  67. GRB 240415A: Swift/UVOT Detection
  68. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  69. GRB 240415A: Earliest optical followup with the Kinder observations
  70. GRB 240414A: GMG observation
  71. EP 240414a: BOOTES-4/MET Optical Upper Limits
  72. EP240414a: EP-FXT follow-up observation
  73. GRB 240415A: OHP/T193 optical observations
  74. GRB 240415A: SAO RAS optical observations
  75. Fermi GRB 240415A: Global MASTER-Net observations report
  76. GRB 240414A: Swift/UVOT Detection
  77. GRB 240415A: Prompt Swift-XRT observations
  78. GRB 240415A: Swift detection of a burst
  79. EP240413a: Upper limits from GECAM-B Observation
  80. EP 240414a: NOT optical counterpart confirmation
  81. GRB 240414A: Swift-XRT refined Analysis
  82. GRB240414A : J-band upper limits from WINTER
  83. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  84. EP240413A: GOTO optical upper limits
  85. Fermi trigger No 734754044: Global MASTER-Net observations report
  86. Swift GRB 240414A: Global MASTER-Net observations report
  87. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  88. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  89. EP240414a: EP-WXT detection of a fast X-ray transient
  90. IPN triangulation of GRB 240411A
  91. GRB 240414A : MITSuME Akeno optical upper limits
  92. EP240413a: EP-WXT detection of a fast X-ray transient
  93. GRB 240414A: Swift detection of a burst
  94. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  95. EP240408a: GSP optical upper limit
  96. GRB 240411B: Kinder observations with Lulin observatory
  97. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  98. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  99. IceCube Alert 240412.23: Global MASTER-Net observations report
  100. GRB 240411B: Swift-BAT refined analysis

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