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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"

6405 results found.

  1. GRB 220219B: Swift-XRT observations
  2. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  3. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  4. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  5. ZTF22aaajecp: GIT optical follow-up observations
  6. GRB 220211A: Fermi GBM observation
  7. GRB 220209A: Fermi-LAT detection
  8. GRB 220210A: Fermi-LAT detection
  9. Fermi GRB 220211A: Global MASTER-Net observations report
  10. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  11. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  12. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  13. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  14. GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  15. GRB 220118A: Fermi GBM detection
  16. GRB 220118A: GIT optical observations
  17. GRB 220118A: Enhanced Swift-XRT position
  18. GRB 220118A: MITSuME Akeno optical observation
  19. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  20. GRB 220117B: Swift-XRT refined Analysis
  21. GRB 220117A: Swift-XRT refined Analysis
  22. Konus-Wind detection of GRB 220101A
  23. GRB 220107A: SAO RAS optical observations
  24. Konus-Wind detection of GRB 220107A
  25. Confirmation of the X-ray afterglow of GRB 220107B
  26. GRB 220107A: further SAO RAS optical observations
  27. GRB 220107A: SAO RAS optical observations
  28. GRB 220101A: SAO RAS optical observations
  29. GRB 220107A: Swift/UVOT Detection
  30. GRB 220107B: Fermi GBM observations
  31. GRB 220107B: Swift-XRT afterglow detection
  32. GRB 220107A: Swift-XRT afterglow detection
  33. GRB 220107B: Fermi-LAT detection
  34. GRB 220107A: Fermi GBM observations
  35. GRB 220101A: continued 1.3m DFOT Optical Observations
  36. GRB 220104A: Fermi GBM Observation
  37. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  38. GRB 220101A: iTelescope optical observations
  39. GRB 220101A: 1.3m DFOT observations
  40. GRB 211229B: Fermi GBM observation
  41. Alert from the HAWC Burst Monitor HAWC-220103A
  42. GRB 220101A: Swift-XRT refined Analysis
  43. GRB 220101A: Fermi-LAT detection
  44. GRB 211229A: Swift-XRT and UVOT observations
  45. GRB 211229A: Fermi GBM observation
  46. GRB 211227A: Swift-XRT refined Analysis
  47. GRB 211221A: Swift-XRT refined Analysis
  48. IceCube-211216B: No significant detection in HAWC
  49. IceCube-211216A: No significant detection in HAWC
  50. GRB 211216A: Fermi GBM observation
  51. GRB 211106A: XMM-Newton monitoring campaign detections
  52. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  53. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  54. IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  55. GRB 211211A: HCT and GIT optical follow up observations
  56. GRB 211211A: Swift-XRT refined Analysis
  57. GRB 211211A: Fermi GBM observation
  58. IceCube-211208A: No significant detection in HAWC
  59. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  60. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  61. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  62. GRB 211204C: Fermi GBM detection
  63. GRB 211207A: Swift-XRT refined Analysis
  64. GRB 211206A: AstroSat CZTI detection
  65. GRB 211124A: Fermi GBM Observation
  66. IceCube-211125A: No significant detection in HAWC
  67. GRB 211129A: Swift-XRT refined Analysis
  68. GRB 211129A: Fermi GBM observation
  69. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  70. GRB 211023A: Xinglong 2.16m optical observations
  71. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  72. GRB 211120548: Fermi GBM observation
  73. Chandra observations of GRB 210905A
  74. GRB 211118A: Fermi GBM detection
  75. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  76. HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  77. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  78. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  79. Fermi trigger No 658755664: Global MASTER-Net observations report
  80. GRB 211023A: classification and SPI-ACS/INTEGRAL registration
  81. GRB 211106A: Swift/UVOT upper limits
  82. GRB 211107B: Swift-XRT afterglow detection
  83. GRB 211106A: Swift-XRT afterglow detection
  84. GRB 211023A: SAO RAS optical observations
  85. GRB 211107B: Swift-XRT observations
  86. GRB 211106A: Swift-XRT observations
  87. Swift Trigger 1082569 is probably not a GRB
  88. GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
  89. GRB 211023A: 1.3m DFOT Optical Observations
  90. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  91. GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  92. GRB 211024A: Possible afterglow candidate from GIT
  93. GRB 211024A: Swift-XRT observations
  94. GRB 211024A: Fermi GBM detection
  95. GRB 211018A: Swift-XRT observations
  96. GRB 211025A: Swift-XRT refined Analysis
  97. GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
  98. GRB 211024B: Swift-XRT refined Analysis
  99. GRB 210610B: Sintesz-Newton/CrAO optical observations
  100. GRB 211025A: Swift detection of a burst

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