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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"

28086 results found.

  1. GRB 231216A: GIT optical upper limit
  2. GRB 231216A: Swift detection of a burst
  3. Konus-Wind detection of GRB 231215A
  4. GRB 231214A: Swift/UVOT Upper Limits
  5. GRB 231205B: VZLUSAT-2 detection
  6. GRB 231204A: VZLUSAT-2 detection
  7. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  8. GRB 231215A: Fermi GBM observation
  9. GRB 231215A : OHP/T193 optical afterglow detection
  10. GRB 231215A: Swift/UVOT Detection
  11. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  12. GRB 231215A: Swift-XRT refined Analysis
  13. GRB 231215A: AKO Optical Upper Limit
  14. GRB 231214A: Fermi GBM observation
  15. GRB 231215A: Enhanced Swift-XRT position
  16. Fermi trigger No 724326442: Global MASTER-Net observations report
  17. GRB 231214A: REM optical/NIR upper limits
  18. GRB 231215A: GROWTH-India optical follow-up
  19. GRB 231215A : Nanshan/HMT optical observations
  20. GRB 231215A: AstroSat CZTI detection
  21. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  22. GRB 231214A: Swift-XRT refined Analysis
  23. GRB 231215A: Mondy optical bright afterglow detection
  24. GRB 231214A: AstroSat CZTI detection
  25. GRB 231215A: Swift-XRT observations
  26. GRB 231215A: Swift detection of a burst
  27. GRB 231214A: Enhanced Swift-XRT position
  28. GRB 231214B: Swift/BAT-GUANO detection of a burst
  29. GRB 231214A: Swift detection of a burst
  30. GRB 231210B: REM optical/NIR upper limits
  31. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  32. LIGO/Virgo/KAGRA S231213ap: Updated Sky localization
  33. LIGO/Virgo/KAGRA S231213ap: Identification of a GW compact binary merger candidate
  34. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  35. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  36. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  37. GRB 231212A: GECAM-C detection of a likely short burst
  38. GRB 231210B: MeerLICHT afterglow observations
  39. GRB 231210B: Swift-BAT refined analysis
  40. GRB 231210B: Swift-XRT refined Analysis
  41. GRB 231210B: Enhanced Swift-XRT position
  42. GRB 231210B: VLT/X-shooter redshift
  43. GRB 231210B: Swift detection of a burst with optical counterpart
  44. Swift GRB231210.90: Global MASTER-Net OT detection
  45. IPN triangulation of GRB 231129C
  46. GRB231205B: Swift/UVOT Upper Limits
  47. GRB 231208A: Glowbug gamma-ray detection
  48. LIGO/Virgo/KAGRA S231206ca: Updated Sky localization
  49. GRB 231205B: Swift-BAT refined analysis
  50. GRB 231205B: 1.3m DFOT Optical upper limit
  51. LIGO/Virgo/KAGRA S231206cc: Updated Sky localization and Source Classification
  52. GRB 231206A: joint location of multiple instruments by ETJASMIN
  53. GRB 231205B: optical upper limit in TSHAOand AbAO
  54. LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate
  56. GRB231115A: TURBO Pre-Burst Optical Upper Limits
  57. GRB 231205B: Swift-XRT refined Analysis
  58. Fermi-LAT gamma-ray observations of IceCube-231202A
  59. GRB 231205B: REM optical/NIR upper limits
  60. GRB 231129C: ASIM MXGS observation and localization
  61. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  62. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  63. GRB 231205B : MITSuME Akeno optical upper limits
  64. GRB 231206A: GECAM-B detection of a short burst
  65. GRB 231205B: Zadko observatory - Gingin optical observations
  66. GRB 231205B: Gaoyazi/GOT optical upper limit
  67. GRB 231205B: Nanshan/HMT optical upper limit
  68. GRB 231205B: LCOGT Optical Upper Limits
  69. GRB 231205A: DDOTI Upper Limits on the Afterglow
  70. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  71. GRB 231205B: Enhanced Swift-XRT position
  72. GRB 231204A: Glowbug gamma-ray detection
  73. Fermi-LAT daily aperture light curve of T CrB now available
  74. GRB 231205B: AKO Optical Upper Limit
  75. GRB 231205B: Swift detection of a burst
  76. GRB 231205A: joint location of multiple instruments by ETJASMIN
  77. GRB 231205A: GECAM-B detection of a short burst
  78. Fermi trigger No 723326169: Global MASTER-Net observations report
  79. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  80. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  81. GRB 231203A: Fermi GBM Observation
  82. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  83. GRB 231129C: Swift-XRT afterglow detection
  84. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  85. GRB 231129A: VZLUSAT-2 detection
  86. GRB 231129B: Swift-XRT observations
  87. GRB 231128A: VZLUSAT-2 detection
  88. Optical transient in the field of Messier 31, likely a new blazar: back to bright state
  89. GRB 231129A : MITSuME Akeno optical upper limits
  90. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  91. GRB 231129A: Swift-BAT refined analysis
  92. GRB 231129A: JinShan optical upper limit
  93. GRB 231129C: Glowbug gamma-ray detection
  94. GRB 231129C: Swift-XRT observations
  95. GRB 231129A: Swift/UVOT Upper Limits
  96. GRB 231129A: optical upper limit in Mondy observatory
  97. GRB 231129C: Fermi GBM Observation of a very bright GRB
  98. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  99. GRB 231129C: MAXI/GSC detection
  100. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)

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