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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"

18516 results found.

  1. EP241223a: Mondy AZT-33IK optical observations
  2. GRB 241029A: LCO optical observation
  3. GRB 241223A: Swift-XRT observations
  4. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  5. GRB 241029A: AbAO AS-32 optical observations
  6. EP241223a
  7. EP241223a: EP-WXT detection of a fast X-ray transient
  8. GRB241113A: 7DT Optical upper limits
  9. GRB 241105A: JWST photometric observations of the host galaxy
  10. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  11. The EP-WXT trigger 01709129287 is likely a flaring star
  12. EP241217a: Liverpool Telescope optical upper limit
  13. EP241021a: VLA radio detection
  14. GRB 241218A: Mondy AZT-33IK optical upper limit
  15. EP241217a : Leavitt Observatory optical upper limit
  16. EP241217a: 1.6m Mephisto multi-band optical observations
  17. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  18. GRB 241218A: Swift/UVOT Upper Limits
  19. EP241217a: optical upper limit with the Liverpool Telescope
  20. GRB 241209B: EP-FXT afterglow detection
  21. GRB 241218A: NOT optical upper limits
  22. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  23. EP 241217a: NIR detection with P200/WIRC
  24. EP 241217a: Possible J-band detection with WINTER
  25. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  26. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  27. GRB 241217A / EP241217b: NOT optical upper limits
  28. GRB 241218A: REM optical upper limit
  29. GRB 241217A/EP241217b: REM optical/NIR upper limits
  30. EP241217a: REM optical/NIR upper limits
  31. GRB 241217a: Liverpool Telescope optical follow-up
  32. EP241217a: Liverpool Telescope optical follow-up
  33. GRB 241218A: Swift-XRT refined Analysis
  34. EP241217a: NOT optical observations
  35. EP241217a: GROWTH-India Telescope optical observations
  36. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  37. EP241119a: 7DT Optical upper limits
  38. GRB 241209A: ATCA radio follow-up observations
  39. EP241217a: Xinglong optical follow-up observations
  40. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  41. GRB 241218A: LCOGT Optical Upper Limit
  42. GRB 241218A: Enhanced Swift-XRT position
  43. GRB 241217A: GMG Optical Upper Limit
  44. GRB 241218A: Swift detection of a burst
  45. GRB 241217A : SVOM/VT optical afterglow detection
  46. GRB 241217A: Swift-XRT afterglow detection
  47. GRB 241217A: LCO optical upper limit
  48. GRB 241217A: GRANDMA/TAROT optical upperlimits
  49. EP241217a: Swift-XRT Detection
  50. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  51. EP241217a: Kinder optical follow-up observations
  52. EP241217A: LCO optical observations
  53. EP241217a: Gemini-North detection of the likely optical counterpart
  54. EP241217a: EP detection of an X-ray transient
  55. The EP-WXT trigger 01709129023 is likely a flaring star
  56. EP241107a: VLA Radio Observation
  57. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  58. GRB 241215A: Mondy AZT-33IK optical observations
  59. GRB 241212A: Swift-XRT observations
  60. The EP-WXT trigger 01709128948 is likely a flaring star
  61. GRB 241215A: Nanshan/HMT optical upper limit
  62. GRB 241215A: Montarrenti Observatory optical upper limit
  63. GRB 241215A: GROWTH-India telescope optical upper limit
  64. The EP-WXT trigger 01709128921 is likely a flaring star
  65. GRB 241213B: Swift-XRT observations
  66. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  67. EP trigger ID 01709128824 is not a real source
  68. GRB 241213A: Swift/UVOT Upper Limits
  69. EP241208a: NOT optical upper limits
  70. GRB 241213A: LCOGT Optical Upper Limits
  71. EP241213a: EP detection of An X-ray Transient
  72. GRB 241213A: REM optical/NIR upper limits
  73. GRB 241213A: Enhanced Swift-XRT position
  74. GRB241212A: OHP/T193 optical observations
  75. GRB 241213A: SAO RAS optical upper limit
  76. GRB 241213A: Swift detection of a burst
  77. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  78. GRB 241209B: GRANDMA/TRT upper limit
  79. GRB 241212A: SVOM detection of a bright long burst
  80. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  81. GRB 241209D: REM optical/NIR upper limits
  82. GRB 241209B: Swift-XRT afterglow detection
  83. GRB 241209A: Swift-XRT refined Analysis
  84. EP241208a: Optical upper limit with Kinder observations
  85. GRB 241209A: EP-FXT follow-up observations
  86. EP241208a: EP-FXT follow-up observations
  87. Fermi trigger No 755485387: Global MASTER-Net observations report
  88. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  89. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  90. GRB 241209D: COLIBRÍ detection of the afterglow
  91. GRB 241209A: COLIBRÍ Optical Upper Limit
  92. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  93. GRB 241209A: GRANDMA/TAROT upper limit
  94. GRB 241209E: Fermi GBM Final Real-time Localization
  95. GRB 241209A: REM optical/NIR observations
  96. GRB 241209D: Enhanced Swift-XRT position
  97. GRB 241209D: Swift detection of a burst
  98. GRB 241209D: Fermi GBM Final Real-time Localization
  99. GRB 241209A: Enhanced Swift-XRT position
  100. GRB 241114B: cubesat Avion detection

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