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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"

888 results found.

  1. GRB 241207C: Tiled Swift observations
  2. GRB 241207C: MAXI/GSC detection
  3. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  4. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  5. GRB 240414A: further radio observations with the VLA
  6. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  7. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  9. GRB 240824B: Ondrejov D50 optical limit
  10. GRB 240824B: Fermi GBM Observation
  11. GRB 240824B: Swift-XRT afterglow detection
  12. GRB 240824B: Swift/BAT arcminute localization of a burst
  13. GRB 240824B: MAXI/GSC detection
  14. GRB 240809B: MAXI/GSC detection
  15. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  16. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  17. GRB 240514E: A possible candidate BD-21 1074
  18. MAXI GRB240514.78: Global MASTER-Net observations report
  19. GRB 240514E: MAXI/GSC detection of a probable afterglow
  20. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  21. GRB 240414A: NOEMA detection
  22. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  23. GRB 240414A: radio detection with the VLA
  24. GRB 240414A: AMI-LA radio observations
  25. GRB 240414A: LBT optical detection
  26. GRB 240414A: Glowbug gamma-ray detection
  27. GRB 240414A: Swift-BAT refined analysis
  28. GRB 240414A: AbAO optical upprer limit
  29. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  30. GRB 240414A: GMG observation
  31. EP 240414a: BOOTES-4/MET Optical Upper Limits
  32. GRB 240414A: Fermi GBM Observation
  33. GRB 240414A: Photometric observation from 2.2m CAHA
  34. GRB 240414A: Swift/UVOT Detection
  35. GRB 240414A: Mondy optical observations
  36. GRB 240414A: AKO Optical Upper Limit
  37. X-ray transient EP 240414a - GTC spectroscopic observations
  38. EP 240414a: NOT optical counterpart confirmation
  39. GRB 240414A: Swift-XRT refined Analysis
  40. GRB240414A : J-band upper limits from WINTER
  41. GRB 240414A: Enhanced Swift-XRT position
  42. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  43. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  44. GRB 240414A: Skynet Optical Afterglow Observations
  45. Swift GRB 240414A: Global MASTER-Net observations report
  46. GRB 240414A : MITSuME Akeno optical upper limits
  47. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  48. GRB 240414A : OHP/T193 redshift determination
  49. GRB 240414A : OHP/T193 optical counterpart detection
  50. GRB 240414A: Swift detection of a burst
  51. GRB 240309A: MAXI/GSC detection
  52. GRB 240225B: Swift-XRT afterglow detection
  53. GRB 240225B: Glowbug gamma-ray detection
  54. GRB 240225B: Swift ToO observations
  55. Konus-Wind detection of GRB 240225B (long)
  56. GRB 240225B: VLT/X-shooter redshift
  57. GRB 240225B : MITSuME Akeno optical afterglow candidate detection
  58. GRB 240225B: 3.6m DOT observation
  59. GRB 240225B: NOT optical observations
  60. GRB 240225B: Nanshan/HMT optical afterglow detection
  61. GRB 240225B: CALET Gamma-Ray Burst Monitor detection
  62. GRB 240225B: Swift-XRT observations
  63. GRB 240225B: GOTO detection of a candidate optical afterglow
  64. GRB 240225B: AstroSat CZTI detection
  65. GRB 240225B: Tiled Swift observations
  66. GRB 240225B: MAXI/GSC detection
  67. GRB 240128A: Further Swift-XRT observations
  68. GRB 240214A: Tiled Swift observations
  69. GRB 240214A/1H 0451-560: MAXI/GSC detection
  70. GRB 240128A: Glowbug gamma-ray detection
  71. GRB 240128A: Swift-XRT observations
  72. GRB 240128A: GRBAlpha detection
  73. GRB 240128A: Tiled Swift observations
  74. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  75. GRB 240128A: MAXI/GSC detection
  76. GRB 240122A: ATCA detection of radio counterpart
  77. GRB240122A: PRIME near infrared detection
  78. GRB 240122A: Swift/UVOT Upper Limits
  79. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  80. GRB 240122A: Swift-XRT afterglow detection
  81. GRB 240122A: VLT/X-shooter redshift confirmation
  82. GRB 240122A: Redshift from OSIRIS+/GTC
  83. GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
  84. GRB 240122A: GOTO optical counterpart candidate
  85. GRB 240122A: Tiled Swift observations
  86. GRB 240122A: MAXI/GSC detection
  87. GRB 240107A: VZLUSAT-2 detection
  88. GRB 240114A: MAXI/GSC detection
  89. GRB 240107A: AstroSat CZTI detection
  90. GRB 240107A: MAXI/GSC detection
  91. IPN triangulation of GRB 231129C
  92. GRB 231129C: ASIM MXGS observation and localization
  93. Konus-Wind detection of GRB 231129C
  94. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  95. GRB 231129B: Swift-XRT observations
  96. GRB 231129C: AGILE detection
  97. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  98. GRB 231129C: MASTER OT detection
  99. GRB 231129C: Fermi-LAT detection
  100. GRB 231129C: GRBAlpha detection

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