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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"
  1. GRB 200907C: Fermi GBM Final Real-time Localization
  2. Correction to GCN 28387: GRB 200907B GROWTH-India optical upper limit
  3. GRB200907A: GROWTH-India optical upper limit
  4. Fermi GRB 200906A: Global MASTER-Net observations report
  5. GRB 200907B: Prompt enhanced Swift-XRT position
  6. GRB 200907B: Swift detection of a short burst
  7. IPN triangulation of GRB 200903E
  8. GRB 200906A: EMIR/GTC NIR upper limit
  9. GRB 200906A: LBT near-infrared upper limit
  10. GRB 200906A: Swift-BAT refined analysis
  11. GRB 200906A: Swift/UVOT Upper Limits
  12. GRB 200907A: AGILE/MCAL detection of a burst
  13. GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit
  14. GRB 200906A: OSN 1.5m Upper Limit
  15. GRB 200906A: Swift-XRT refined Analysis
  16. GRB 200906A: Fermi GBM detection
  17. GRB 200906A: Enhanced Swift-XRT position
  18. GRB 200906A: Nanshan/NEXT optical upper limit
  19. GRB 200906A: Swift detection of a burst
  20. GRB 200906A: Fermi GBM Final Real-time Localization
  21. Baksan Neutrino Observatory Alert 200905.99: Global MASTER-Net observations report
  22. Swift Triggers 994723-994725 and 994727 are not GRBs.
  23. GRB 200903E: AstroSat CZTI detection
  24. Fermi GRB 200904A: Global MASTER-Net observations report
  25. GRB 200904A: Fermi GBM Final Real-time Localization
  26. Fermi GRB 200903C: Global MASTER-Net observations report
  27. GRB 200903D: MAXI/GSC detection
  28. GRB 200903A: Fermi GBM detection
  29. GRB 200903C: Fermi GBM Final Real-time Localization
  30. GRB 200903A: Swift-BAT refined analysis
  31. GRB 200829A: optical observations, a light curve in R-filter
  32. GRB 200903B: Insight-HXMT/HE detection
  33. GRB 200903A: CALET Gamma-Ray Burst Monitor detection
  34. AGILE detection of a burst (AGILE trigger no. 526185273)
  35. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  36. GRB200817B: AstroSat CZTI detection
  37. Fermi GRB 200903B: Global MASTER-Net observations report
  38. GRB 200903B: Fermi GBM Final Real-time Localization
  39. Swift GRB200903.03: Global MASTER-Net observations report
  40. GRB 200903A: Swift detection of a burst
  41. GRB 200903A: Fermi GBM Final Real-time Localization
  42. GRB 200901A: MASTER OT early detection
  43. GRB 200901B: Swift-XRT refined Analysis
  44. INTEGRAL Weak#8699: AROMA-N Optical Observation
  45. GRB 200901B: Swift-BAT refined analysis
  46. GRB 200901A: Swift-BAT refined analysis
  47. GRB 200901B: Swift/UVOT Detection
  48. GRB 200901A: Swift/UVOT Detection
  49. GRB 200901A: Swift-XRT refined Analysis
  50. GRB 200901A: Fermi GBM observation
  51. GRB 200901B: Enhanced Swift-XRT position
  52. GRB 200829A: Swift/UVOT-XRT photometric redshift
  53. GRB 200901B: Swift detection of a burst
  54. GRB 200901A: Swift-XRT observations
  55. GRB 200901A: Swift detection of a burst
  56. Swift GRB200901.16: Global MASTER-Net observations report
  57. GRB 200829A: Koshka Zeiss-1000 optical observations
  58. Fermi GBM trigger 620564765/200831463 is not a GRB
  59. GRB 200829A: Liverpool Telescope observations
  60. GRB 200829A: Continued Nanshan/NEXT optical observations
  61. GRB 200829A: Kitab optical upper limit
  62. GRB 200829A: further SAO RAS optical observations
  63. Fermi GRB 200830A: Global MASTER-Net observations report
  64. GRB 200829A: Fermi GBM detection
  65. GRB 200829A: Swift-BAT refined analysis
  66. GRB 200829A: Nanshan/NEXT optical observations
  67. Konus-Wind detection of GRB 200829A (a clone of GRB 200826B?)
  68. GRB 200829A: SAO RAS optical observations
  69. GRB 200830A: BALROG localization (Fermi Trigger 620474063 / GRB 200830413)
  70. GRB 200830A: Fermi GBM Final Real-time Localization
  71. GRB 200826A
  72. GRB 200829A: THO optical observatios
  73. GRB 200829A: Swift-XRT refined Analysis
  74. GRB200829A: optical afterglow detection
  75. GRB 200829A: Global MASTER-Net OT detection
  76. GRB 200829A: AGILE/MCAL detection
  77. GRB 200829A: Enhanced Swift-XRT position
  78. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  79. GRB 200829A: Swift/UVOT Detection
  80. Fermi trigger No 620402299: Global MASTER-Net observations report
  81. Swift GRB 200829A: Global MASTER-Net observations report
  82. GRB 200829A: TSHAO optical observations
  83. GRB 200829A: Swift detection of a burst with an optical afterglow
  84. GRB 200826A: Kitab optical observations
  85. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  86. Konus-Wind detection of GRB 200826B
  87. IPN triangulation of GRB 200826B
  88. GRB 200826A: VLA Detection at 6 GHz
  89. GRB 200826A: further analysis of the Konus-Wind data and classification
  90. GRB 200826A: Swift-XRT afterglow detection
  91. GRB 200824A: Insight-HXMT/HE detection
  92. GRB 200826B: Fermi GBM detection
  93. Fermi GRB 200826B: Global MASTER-Net observations report
  94. Fermi GRB 200824A: Global MASTER-Net observations report
  95. GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
  96. Konus-Wind detection of GRB 200826A
  97. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  98. GRB 200826B: Fermi GBM Final Real-time Localization
  99. IPN triangulation of GRB 200826A (short/bright)
  100. GRB 200826A: Tiled Swift observations

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