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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

3381 results found.

  1. GRB 250314A: REM optical/NIR upper limits
  2. EP 250317B: Fading optical counterpart detection by LCO
  3. The EP-WXT trigger 01709132801 is likely a flaring star
  4. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  5. GRB 250314A: EP-FXT afterglow detection
  6. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  7. EP250315a: optical counterpart candidate detected by Gemini North
  8. EP250315a: Einstein Probe detection of an X-ray transient
  9. Konus-Wind detection of GRB 250313A
  10. Konus-Wind detection of GRB 250308A
  11. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  12. EP250304a: Pan-STARRS r and i-band imaging and photometry
  13. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  14. The EP-WXT trigger 01709132551 is not a real source
  15. EP250311a/GRB 250311A: EP-FXT follow-up observation
  16. EP250302a: Chandra X-ray Detection
  17. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  18. EP250311a: Global MASTER-Net observations report
  19. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  20. EP250304a: Chandra detection
  21. GRB 250311A/EP250311a: TRT optical upper limit
  22. EP250311a/GRB 250311A: EP-WXT detection
  23. The EP-WXT trigger 01709132425 is not a real source
  24. Konus-Wind detection of GRB 250309B
  25. EP250308a: Global MASTER-Net observations report
  26. EP250308a: GSP optical upper limit
  27. EP250308a: FTW optical and NIR upper limits
  28. EP250308a: Einstein Probe detection of an X-ray transient
  29. EP250308a: NOT optical upper limit
  30. The EP-WXT trigger 01709132387 is likely a flaring star
  31. Konus-Wind detection of GRB 250306A
  32. EP250304a: MeerKAT detection of a possible radio counterpart
  33. EP250302a:Xinglong optical observations
  34. The EP-WXT trigger 01709132323 is likely a flaring star
  35. EP250304A: Upper limits from Fermi-GBM Observations
  36. EP 250304A: Optical counterpart detection by LCO
  37. EP250302A: 1.3m DFOT optical afterglow detection
  38. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  39. Konus-Wind detection of GRB 250222A
  40. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  41. EP250304a: Swift-XRT detection of a fading X-ray source
  42. EP250304a: TRT optical counterpart detection
  43. EP250304a: Global MASTER-Net observations report
  44. EP250304a: Einstein Probe detection of an X-ray transient
  45. The EP-WXT trigger 01709132212 is not a real source
  46. EP250302a : GIT optical follow-up
  47. EP250302a: VLT/X-shooter redshift confirmation
  48. EP250302a: Kinder optical follow-up observations
  49. EP250302a: Swift/UVOT detection
  50. EP250302a: NUTTelA-TAO Early Measurments
  51. EP250302A: VLT/X-shooter tentative redshift
  52. EP250302a: Global MASTER-Net observations report
  53. EP250302a: Xinglong F60B optical observation
  54. EP250302a: Einstein Probe detection of an X-ray transient
  55. GRB 250226A: GRANDMA Optical Observations
  56. EP250302a: Montarrenti Observatory optical detection
  57. EP250302a: FTW optical and NIR detection
  58. EP250302a: Nanshan/HMT optical counterpart detection
  59. The EP-WXT trigger 01709132140 is likely a flaring star
  60. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  61. EP250228a: Optical observations with Kinder and Swift/UVOT
  62. Konus-Wind detection of GRB 250226A
  63. EP250227a: Global MASTER-Net observations report
  64. EP250223A: Upper limits from Fermi-GBM Observations
  65. EP250227a: TRT optical upper limit
  66. EP250227a: Optical upper limits with Kinder observations
  67. EP250227a: NOT optical observations
  68. EP250227a: Einstein Probe detected of a fast X-ray transient
  69. EP250228a: updates on the EP observations
  70. GRB 250226A: Fermi GBM Observation
  71. EP250225a: EP-FXT follow-up observation
  72. EP250223a: J band upper limit by SYSU 80cm telescope
  73. EP250228a: Swift/XRT localisation
  74. EP250228a: Global MASTER-Net observations report
  75. EP250228a: Einstein Probe detection of an X-ray transient
  76. GRB 250226A / EP250226a: LCO detection of the afterglow
  77. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  78. EP250225a: NOT optical candidate counterpart
  79. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  80. EP250225a: TRT optical upper limits
  81. EP250226a/GRB 250226A: Kinder optical follow-up observations
  82. Konus-Wind detection of GRB 250225B
  83. GRB 250226A: GECAM-B detection
  84. GRB 250221A: EP-FXT detection of the X-ray afterglow
  85. EP250226a/GRB 250226A: GSP detects optical counterpart
  86. EP250226a / GRB 250226A: TRT optical counterpart observation
  87. EP250226a: Global MASTER-Net observations report
  88. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  89. EP250225a: Global MASTER-Net observations report
  90. EP250225a: GSP optical upper limit
  91. EP250223a: GMG Optical Observation
  92. EP250225a: Einstein Probe detected of a fast X-ray transient
  93. EP250223a: GROWTH-India Telescope optical observations
  94. EP250215A: J band upper limit by SYSU 80cm telescope
  95. EP250223a: Kinder optical follow-up observations
  96. GRB 250219A: EP-FXT afterglow detection
  97. EP250223a: GOTO optical afterglow detections
  98. EP250223a: TRT optical afterglow observation
  99. EP250223a: refined analysis of the EP-WXT and FXT observations
  100. EP250223a: 1.6m Mephisto and 50cm array observations

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