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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"

4252 results found.

  1. GRB 210207B: optical detection with 3.6m Devasthal Optical Telescope
  2. Fermi GRB 210207A: Global MASTER-Net observations report
  3. GRB 210204A: Optical Observations from HCT
  4. IPN triangulation of GRB 210204A
  5. GRB 210205A: MITSuME Ishigaki optical observation
  6. GRB 210204: Fermi GBM observation
  7. GRB 210204A: GECAM detection
  8. GRB 210204A: BALROG localization (Fermi Trigger 634112970 / GRB 210204270)
  9. GRB 210204A: Fermi GBM Final Real-time Localization
  10. Fermi GBM Observations of a bright burst from SGR J1935+2154
  11. Recent activity of SGR 1935+2154 as observed by CGBM
  12. INTEGRAL detection of a short burst from SGR 1935+2154
  13. GRB 210131A: GECAM detection
  14. Fermi trigger No 633879387: Global MASTER-Net observations report
  15. GECAM observations of SGR 1935+2154
  16. Fermi GBM Observations of SGR J1935+2154
  17. Konus-Wind detection of two bright bursts from SGR 1935+2154
  18. IPN triangulation of a bright burst from SGR 1935+2154
  19. GECAM detection of a short burst probably from SGR 1935+2154
  20. GRB 210120A: Fermi GBM detection
  21. GRB 210126A: GECAM detection
  22. IPN triangulation of GRB 210124B (short)
  23. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  24. GRB 210121A: GECAM detection
  25. GECAM In-Flight Trigger of GRB 210120A
  26. Fermi GRB 210120A: Global MASTER-Net observations report
  27. GRB 210119A (Swift J1851.2-6148): Swift-BAT refined analysis
  28. GECAM detection of a short GRB 210119A or a new SGR candidate Swift J1851.2-6148
  29. GRB 210119A: Fermi GBM observation
  30. Short Fermi GRB 210119A or new SGR Swift J1851.2-6148: Possible MASTER Short OT detection
  31. Swift detection of a new SGR Swift J1851.2-6148 or a short GRB 210119A
  32. ZTF21aaeyldq: observations with the 3.6m Devasthal Optical Telescope
  33. GRB 210112A: OSN second epoch, decay
  34. GRB 210104A: AROMA-N Optical Afterglow Detection
  35. GRB 201227A: continued Chilescope confirmation of variability of possible optical counterpart, redshift estimating
  36. Fermi trigger No 631584650: Global MASTER-Net observations report
  37. GRB 210104A: MASTER OT rebrightening detection
  38. Fermi GRB 210104A: Global MASTER-Net observations report
  39. Fermi GRB 210102C: Global MASTER-Net observations report
  40. MAXI GRB210102.38: Global MASTER-Net observations report
  41. Fermi GRB 210101A: Global MASTER-Net observations report
  42. Fermi trigger No 631119348: Global MASTER-Net observations report
  43. Fermi trigger No 631118376: Global MASTER-Net observations report
  44. Fermi trigger No 631104264: Global MASTER-Net observations report
  45. GRB 201227A: Chilescope optical observations, possible optical counterpart
  46. GRB 201229A: AbAO optical afterglow detection, TSHAO optical upper limit
  47. GRB 201229A: Nanshan/NEXT optical upper limit
  48. GRB 201227A: Swift-XRT observations
  49. Fermi GRB 201229B: Global MASTER-Net observations report
  50. GRB 201229B: BALROG localization (Fermi Trigger 630948017 / GRB 201229639)
  51. GRB 201229B: Fermi GBM Final Real-time Localization
  52. ZTF20acozryr/AT2020yxz (GRB 201103B): Maidanak optical observations
  53. Fermi trigger No 630681391: Global MASTER-Net observations report
  54. GRB 201223A: Mondy and Kitab optical observations
  55. Konus-Wind detection of GRB 201216C
  56. GRB 201216C: AstroSat CZTI detection
  57. Fermi GRB 201216A: Global MASTER-Net observations report
  58. GRB 201015A: 5-GHz radio afterglow detection with the EVN
  59. Swift GRB201209.24: Global MASTER-Net observations report
  60. Swift GRB 201203A: Global MASTER-Net observations report
  61. IceCube-201130A: No significant detection in HAWC
  62. IceCube-201130A: Upper limits from a search for additional neutrino events in IceCube
  63. GRB 201121A: Insight-HXMT/HE detection
  64. INTEGRAL Weak #8831 and #8832: AROMA-N Optical Observation
  65. GRB 201121A: BALROG localization (Fermi Trigger 627614994 / GRB 201121062)
  66. GRB 201121A: Fermi GBM Final Real-time Localization
  67. IceCube-201120A: Upper limits from Fermi-GBM Observations
  68. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  69. ZTF20acozryr/AT2020yxz (GRB 201103B): Mondy continued optical observations
  70. Fermi GRB 201111A: Global MASTER-Net observations report
  71. Swift Trigger 1005428: Detection of SGR 1830-0645
  72. GRB 201104B: MITSuME Akeno optical observation
  73. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  74. IPN triangulation of GRB 201103B (consistent with ZTF20acozryr/AT2020yxz)
  75. Swift Trigger 1004219: Detection of SGR 1830-0645
  76. Swift GRB 201029A: Global MASTER-Net observations report
  77. GRB 201029A: Fermi GBM detection
  78. Fermi trigger No 625695596: Global MASTER-Net observations report
  79. GRB 201027A: Swift-BAT refined analysis
  80. GRB 201027A: 1.5m OSN optical upper limit
  81. GRB 201014A: 2.0m HCT upper limit
  82. GRB 201021C: VLT/X-shooter redshift
  83. GRB 201021C: Swift detection of a burst with an optical counterpart
  84. GRB 201014A: 3.6m DOT Optical Observations
  85. GRB 201013A: 3.6m DOT Optical Observations
  86. GRB 201017A: Swift detection of a burst
  87. Fermi GRB 201016B: Global MASTER-Net observations report
  88. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  89. Swift GRB 201013A: Global MASTER-Net observations report
  90. SGR 1830-0645: Swift/UVOT Upper Limits
  91. GRB 201011A: Fermi GBM detection of a likely Long GRB in the direction of SGR 1830-0645
  92. Fermi trigger No 624139481: AGILE detection
  93. SGR 1830-0645: pre-discovery detection in Swift/BAT
  94. SGR 1830-0645 / GRB 201010A: 1.5m OSN optical upper limit
  95. SGR 1830-0645: Swift-BAT refined analysis
  96. SGR 1830-0645 / GRB 201010A: Kitab optical non-detection
  97. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  98. IceCube-201007A: No significant detection in HAWC
  99. IceCube-200926A: Upper limits from Insight-HXMT Observations
  100. Fermi GRB 201007A: Global MASTER-Net observations report

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