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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"

27395 results found.

  1. GRB 210725A: Swift-BAT refined analysis
  2. GRB 210724A: Swift-BAT refined analysis
  3. GRB 210724A: Afterglow candidate from OSIRIS/GTC
  4. GRB 210725B: Enhanced Swift-XRT position
  5. GRB 210725A: MITSuME Akeno optical upper limits
  6. GRB 210725B: Swift detection of a burst
  7. GRB 210722A: continued Assy optical observations
  8. GRB 210722A: Nanshan/NEXT further optical observations
  9. GRB 210725A: Swift detection of a burst
  10. GRB 210723A: Fermi GBM Observation
  11. GRB210724A: MeerLICHT upper limits
  12. GRB 210724A: Swift detection of a burst
  13. GRB 210723A: Swift-BAT refined analysis
  14. GRB 210722A: continued Assy optical observations
  15. GRB 210723A: Swift-XRT refined Analysis
  16. GRB 210722A: D50 optical detection
  17. GRB 210722A: Fermi GBM observation
  18. GRB 210722A: Swift-BAT refined analysis
  19. GRB 210722A: Kitab optical observations, light curve
  20. GRB 210722A: Redshift from OSIRIS/GTC
  21. GRB 210723A: Swift detection of a burst
  22. GRB 210722A: RATIR Optical Observations
  23. GRB 210722A: Swift-XRT refined Analysis
  24. GRB 210722A: Swift/UVOT Detection
  25. GRB 210722A: GIT optical detection and preliminary analysis
  26. GRB 210722A: Assy optical detection
  27. GRB 210722A: Nanshan/NEXT optical afterglow observations
  28. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  29. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  30. GRB 210719A: GECAM detection
  31. IceCube-210717A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  32. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  33. GRB 210715B: DDOTI Upper Limits on the Afterglow
  34. GRB 210712A: Swift-BAT refined analysis
  35. GECAM detection of a short burst from SGR J1935+2154
  36. GRB 210712A: Swift-XRT refined Analysis
  37. GRB 210712A: Swift/UVOT Upper Limits
  38. GRB 210712A: Enhanced Swift-XRT position
  39. GRB 210704A: classification as long GRB and redshift estimating
  40. GRB 210704A: Lowell Discovery Telescope Optical Observations
  41. GECAM detection of a short burst from SGR J1935+2154
  42. GRB 210712A: Swift detection of a burst
  43. GRB 210709A: AstroSat CZTI detection
  44. GRB210704A: Gemini near-infrared upper limits
  45. Fermi trigger No 647624281: Global MASTER-Net observations report
  46. GECAM detection of a short burst from SGR J1935+2154
  47. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
  48. MAXI GRB210709.93: Global MASTER-Net observations report
  49. GECAM detection of a short burst from SGR 1935+2154
  50. GRB 210708B: Swift-BAT refined analysis
  51. GRB 210708A: Swift/UVOT Upper Limits
  52. GRB 210708A: Swift-BAT refined analysis
  53. Fermi GBM Sub-Threshold Detection of GRB 210708A
  54. Fermi GBM Sub-Threshold Detection of GRB 210707A
  55. IceCube-210629A - Spectroscopic observation of AT2021osi
  56. GRB 210708A: Swift-XRT refined Analysis
  57. GECAM detection of a short burst from SGR 1935+2154
  58. GRB 210707A: A long GRB detected by INTEGRAL
  59. GRB 210708A: Swift detection of a burst
  60. Fermi trigger No 647271699: Global MASTER-Net observations report
  61. GRB 210706A: Fermi GBM observation
  62. GRB 210706A: GIT optical upper limits
  63. GRB 210704A: OAJ T80 multi-color detections
  64. GECAM detection of a bright short burst from SGR 1935+2154
  65. GRB 210706A: Swift-XRT afterglow detection
  66. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  67. GRB 210704A: OSIRIS/GTC spectroscopy
  68. GRB 210704A: RATIR optical upper limits
  69. GRB 210704A: Swift/UVOT Upper Limits
  70. GRB 210704A: TNG detection of the optical afterglow candidate
  71. GRB 210704A: Assy optical afterglow candidate
  72. GRB 210704A: DDOTI upper limit
  73. GRB 210704B: Fermi GBM detection
  74. GRB 210704A: possible local hosts
  75. GRB 210704A: Fermi GBM detection
  76. GRB 210704A: Swift-XRT afterglow detection
  77. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  78. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  79. Fermi trigger No 647108723: Global MASTER-Net observations report
  80. Fermi trigger No 647120009: Global MASTER-Net observations report
  81. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  82. GRB 210702A, Swift-BAT refined analysis
  83. GRB 210702A: Chilescope optical observations
  84. GRB 210702A: iTelescope optical afterglow observations
  85. GRB 210702A: Swift-XRT refined Analysis
  86. GRB 210702A: VLT/X-shooter redshift
  87. GRB 210702A: preliminary Swift/UVOT photometry
  88. GRB210702A: MeerLICHT multi-colour photometry
  89. Swift GRB210702.80: Global MASTER-Net OT detection
  90. GRB 210702A: Swift detection of a burst with a bright optical counterpart
  91. IceCube-210629A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  93. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  94. GRB 210627B: GECAM detection
  95. GRB 210619B: Sayan observatory 1.6-m telescope observations
  96. GRB 210626A: GIT optical upper limit
  97. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  98. GRB 210626A: Swift-XRT afterglow detection
  99. Fermi trigger No 646322348: Global MASTER-Net observations report
  100. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization

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