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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"

39286 results found.

  1. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  2. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  3. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  4. GRB 240425A: Fermi GBM Final Real-time Localization
  5. Fermi trigger No 735697285: Global MASTER-Net observations report
  6. GRB 240419B: Swift-BAT refined analysis
  7. GRB 240421B: Swift-BAT refined analysis
  8. GRB 240422A: Glowbug gamma-ray detection
  9. LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
  10. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  11. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  12. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  13. GRB 240421B: GRBAlpha detection
  14. IceCube Alert 240424.08: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  16. GRB 240419A: Swift-BAT refined analysis
  17. GRB 240418A: Swift-BAT refined analysis
  18. LXT240402A/GRB240402B: Chandra X-ray detection
  19. GRB 240419A: Possible ATCA radio detection
  20. GRB 240421B: ATCA radio observations
  21. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
  23. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  24. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  25. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  27. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  28. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  29. Fermi trigger No 735470374: Global MASTER-Net observations report
  30. GRB 240421A: Glowbug gamma-ray detection
  31. GRB 240414A: radio detection with the VLA
  32. Fermi-LAT gamma-ray observations of IceCube-240419A
  33. GRB 240414A: AMI-LA radio observations
  34. GRB 240414A: LBT optical detection
  35. GRB 240419B : MITSuME Akeno optical upper limits
  36. GRB 240415B: Swift-XRT observations
  37. GRB 240415A: Swift-XRT refined Analysis
  38. Fermi GRB 240422A: Global MASTER-Net observations report
  39. GRB 240421B: AstroSat CZTI detection
  40. GRB 240422A: Fermi GBM Final Real-time Localization
  41. GRB240421B: Zadko Observations
  42. Fermi GRB 240421B: Global MASTER-Net observations report
  43. Swift GRB 240421B: Global MASTER-Net observations report
  44. GRB 240421B: Fermi GBM Observation
  45. GRB 240421B: Swift-XRT refined Analysis
  46. GRB240421B: BOOTES-5/JGT optical upper limit
  47. GRB 240421B: J-band upper limits from WINTER
  48. GRB 240421B: Swift/UVOT Upper Limits
  49. GRB 240421B: Enhanced Swift-XRT position
  50. Fermi GRB 240421A: Global MASTER-Net observations report
  51. EP240420a: TNT upper limit to its optical counterpart
  52. EP240420a: Xinglong decaying optical counterpart
  53. GRB 240421B: Swift detection of a burst
  54. EP240420a: Nanshan optical counterpart observations
  55. GRB 240421A: Fermi GBM Final Real-time Localization
  56. Fermi trigger No 735280430: Global MASTER-Net observations report
  57. GRB240419A: Skynet Optical Afterglow Analysis
  58. GRB240418A - Candidate afterglow from NIRES
  59. IceCube Alert 240419.98: Global MASTER-Net observations report
  60. GRB 240419B: Swift/UVOT Upper Limits
  61. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  62. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 240419A: Swift/UVOT Upper Limits
  64. GRB 240419B: Swift-XRT refined Analysis
  65. GRB 240419B: optical afterglow from the NOT
  66. Swift GRB 240419B: Global MASTER-Net observations report
  67. EP240414A: Terskol Zeiss-2000 optical upper limit
  68. GRB 240419B: Enhanced Swift-XRT position
  69. Swift GRB 240419A: Global MASTER-Net observations report
  70. GRB 240418A: Swift/UVOT Upper Limits
  71. GRB 240419A: REM NIR afterglow detection
  72. GRB 240419A: Swift-XRT refined Analysis
  73. GRB 240418A: Swift-XRT refined Analysis
  74. GRB 240419B: Swift detection of a burst
  75. GRB 240411B: Swift/UVOT Detection
  76. GRB240418A: YAHPT Upper Limits
  77. GRB 240419A: VLT/UVES redshift of z = 5.178
  78. GRB 240419A: VLT optical afterglow detection
  79. GRB 240419A: Enhanced Swift-XRT position
  80. Fermi trigger No 735089036: Global MASTER-Net observations report
  81. GRB 240419A: Prompt enhanced Swift-XRT position
  82. GRB 240419A: Swift detection of a burst
  83. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  84. GRB 240418A: NOT optical upper limits
  85. GRB 240418A: Enhanced Swift-XRT position
  86. GRB 240418A: AKO Upper Limit
  87. GRB 240411A: GOTO early optical upper limits
  88. Swift GRB240418.85: Global MASTER-Net observations report
  89. GRB 240418A: Swift detection of a burst
  90. Fermi GRB 240417A: Global MASTER-Net observations report
  91. EP240416A: Terskol Zeiss-2000 optical upper limit
  92. EP240416A: Khureltogoot optical upper limit
  93. Improved IPN triangulation of GRB 240411A
  94. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  95. GRB 240417A: Fermi GBM Final Real-time Localization
  96. GRB 240415A: Glowbug gamma-ray detection
  97. GRB 240414A: Glowbug gamma-ray detection
  98. GRB 240415B: GECAM-B detection
  99. EP 240416a: Xinglong and NOT decaying optical counterpart
  100. GRB 240415A: Swift-BAT refined analysis

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