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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"

37347 results found.

  1. GRB 240513B: Fermi GBM Final Real-time Localization
  2. GRB 240513A: AstroSat CZTI detection
  3. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  4. GRB 240511A: J-band observations with WINTER
  5. GRB 240511A: Enhanced Swift-XRT position
  6. GRB 240511A : MITSuME Akeno optical upper limits
  7. GRB 240511A: Swift-XRT refined Analysis
  8. GRB 240511A: optical afterglow detection from the NOT
  9. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  10. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  11. Fermi GBM trigger 737105243/240511311 is not a GRB
  12. Fermi GRB 240511A: Global MASTER-Net observations report
  13. Swift GRB 240511A: Global MASTER-Net observations report
  14. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  15. GRB 240511A: Prompt enhanced Swift-XRT position
  16. GRB 240511A: Swift detection of a burst
  17. GRB 240511A: Fermi GBM Final Real-time Localization
  18. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  19. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  20. EP240506a: CrAO ZTSH optical upper limit
  21. GRB 240504A: Fermi GBM Observation
  22. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  23. EP240506a: Optical upper limit with Kinder observations
  24. IPN triangulation of GRB 240504A
  25. GRB 240502A: 1.3m DFOT Optical upper limit
  26. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  27. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  28. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  29. Fermi GRB 240504A: Global MASTER-Net observations report
  30. GRB 240503A: AstroSat CZTI detection
  31. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  32. GRB 240504A: Fermi GBM Final Real-time Localization
  33. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  34. GRB 240502A: GOTO optical upper limit
  35. GRB 240502A: Fermi GBM Observation
  36. GRB 240415A 1.3m DFOT Optical upper limit
  37. GRB 240502C: GOTO possible optical counterpart candidates
  38. Fermi GRB 240502B: Global MASTER-Net observations report
  39. GRB 240502C: Fermi GBM Final Localization
  40. Fermi GRB 240502A: Global MASTER-Net observations report
  41. GRB 240501B: GRBAlpha detection
  42. GRB 240430A: GRBAlpha detection
  43. GRB 240502B: Fermi GBM Final Real-time Localization
  44. GRB 240502A long GRB detected by INTEGRAL
  45. GRB 240502A: Fermi GBM Final Real-time Localization
  46. Fermi GRB 240501A: Global MASTER-Net observations report
  47. GRB 240426A: VZLUSAT-2 detection
  48. GRB 240425A: VZLUSAT-2 detection
  49. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  50. GRB240430A: Fermi GBM Final Localization
  51. GRB 240501B: AstroSat CZTI detection
  52. GRB 240501A: Fermi GBM Final Real-time Localization
  53. GRB 240408B: VZLUSAT-2 detection
  54. GRB 240407A: VZLUSAT-2 detection
  55. X-ray transient EP240414a: Detection of associated supernova
  56. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  57. Additional DECam GW-MMADS Candidates from three nights of observations
  58. GRB 240425A: GRBAlpha detection
  59. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
  60. GRB 240429A: Fermi GBM Final Real-time Localization
  61. Fermi GRB 240428A: Global MASTER-Net observations report
  62. GRB 240428A: Fermi GBM Final Real-time Localization
  63. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  64. GRB 240426A: AstroSat CZTI detection
  65. LIGO/Virgo/KAGRA S240422ed: BOOTES-4/MET Optical Upper Limits for EP240426a
  66. GRB 240414A: NOEMA detection
  67. LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
  68. LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
  69. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
  70. S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
  71. S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
  72. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  73. LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
  74. GRB 240425A: Fermi GBM Final Real-time Localization
  75. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  76. GRB 240419B: Swift-BAT refined analysis
  77. GRB 240421B: Swift-BAT refined analysis
  78. GRB 240422A: Glowbug gamma-ray detection
  79. LIGO/Virgo/KAGRA S240422ed: Vetting of DECam Candidates Using Real-Time Resources and SAGUARO Infrastructure
  80. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  81. LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
  82. GRB 240421B: GRBAlpha detection
  83. GRB 240419A: Swift-BAT refined analysis
  84. GRB 240418A: Swift-BAT refined analysis
  85. LXT240402A/GRB240402B: Chandra X-ray detection
  86. GRB 240419A: Possible ATCA radio detection
  87. GRB 240421B: ATCA radio observations
  88. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  89. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  90. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  91. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  92. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
  94. GRB 240421A: Glowbug gamma-ray detection
  95. GRB 240414A: radio detection with the VLA
  96. GRB 240414A: AMI-LA radio observations
  97. GRB 240414A: LBT optical detection
  98. GRB 240419B : MITSuME Akeno optical upper limits
  99. GRB 240415B: Swift-XRT observations
  100. GRB 240415A: Swift-XRT refined Analysis

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