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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"

19600 results found.

  1. EP240702a: 7DT Optical upper limits
  2. GRB 240606B: 7DT Optical upper limits
  3. GRB241229B: UVOT upper limits
  4. GRB 241228B: Swift-XRT afterglow detection
  5. GRB 241229A: Swift ToO observations
  6. GRB 241228A: Mondy optical afterglow observations
  7. GRB 241229A: GOTO optical upper limits
  8. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  9. GRB 241228A: NOT optical upper limits
  10. GRB 241228B: LCO optical observation
  11. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  12. GRB 241229A: SVOM detection of a long burst
  13. GRB241228B: GROWTH-India Telescope optical observations
  14. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  15. GRB 241228A: GROWTH-India telescope optical upper limit
  16. GRB 241228B: Swift ToO observations
  17. GRB 241228B: TRT optical counterpart confirmation
  18. GRB 241228A: Swift-XRT refined Analysis
  19. GRB 241228A: Swift/UVOT Upper Limits
  20. GRB 241228A: Enhanced Swift-XRT position
  21. GRB 241228A: Swift detection of a burst
  22. EP241223a: Mondy AZT-33IK optical observations
  23. GRB 241029A: LCO optical observation
  24. GRB 241223A: Swift-XRT observations
  25. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  26. GRB 241029A: AbAO AS-32 optical observations
  27. EP241223a
  28. EP241223a: EP-WXT detection of a fast X-ray transient
  29. GRB241113A: 7DT Optical upper limits
  30. GRB 241105A: JWST photometric observations of the host galaxy
  31. GRB 241223A: Swift ToO observations
  32. EP241217a: Liverpool Telescope optical upper limit
  33. EP241021a: VLA radio detection
  34. GRB 241218A: Mondy AZT-33IK optical upper limit
  35. EP241217a : Leavitt Observatory optical upper limit
  36. EP241217a: 1.6m Mephisto multi-band optical observations
  37. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  38. GRB 241218A: Swift/UVOT Upper Limits
  39. EP241217a: optical upper limit with the Liverpool Telescope
  40. GRB 241218A: NOT optical upper limits
  41. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  42. EP 241217a: NIR detection with P200/WIRC
  43. EP 241217a: Possible J-band detection with WINTER
  44. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  45. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  46. GRB 241217A / EP241217b: NOT optical upper limits
  47. GRB 241218A: REM optical upper limit
  48. GRB 241217A/EP241217b: REM optical/NIR upper limits
  49. EP241217a: REM optical/NIR upper limits
  50. GRB 241217a: Liverpool Telescope optical follow-up
  51. EP241217a: Liverpool Telescope optical follow-up
  52. EP241217a: NOT optical observations
  53. EP241217a: GROWTH-India Telescope optical observations
  54. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  55. EP241119a: 7DT Optical upper limits
  56. EP241217a: Xinglong optical follow-up observations
  57. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  58. GRB 241218A: LCOGT Optical Upper Limit
  59. GRB 241218A: Enhanced Swift-XRT position
  60. GRB 241217A: GMG Optical Upper Limit
  61. GRB 241218A: Swift detection of a burst
  62. GRB 241217A : SVOM/VT optical afterglow detection
  63. GRB 241217A: Swift-XRT afterglow detection
  64. GRB 241217A: LCO optical upper limit
  65. GRB 241217A: GRANDMA/TAROT optical upperlimits
  66. EP241217a: Swift-XRT Detection
  67. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  68. EP241217a: Kinder optical follow-up observations
  69. EP241217A: LCO optical observations
  70. EP241217a: Gemini-North detection of the likely optical counterpart
  71. EP241217a: EP detection of an X-ray transient
  72. EP241107a: VLA Radio Observation
  73. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  74. GRB 241215A: Mondy AZT-33IK optical observations
  75. GRB 241212A: Swift-XRT observations
  76. GRB 241215A: Nanshan/HMT optical upper limit
  77. GRB 241215A: Montarrenti Observatory optical upper limit
  78. GRB 241215A: GROWTH-India telescope optical upper limit
  79. GRB 241213B: Tiled Swift observations
  80. GRB 241213A: Swift/UVOT Upper Limits
  81. EP241208a: NOT optical upper limits
  82. GRB 241212A: Swift ToO observations
  83. GRB 241213A: LCOGT Optical Upper Limits
  84. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  85. EP241213a: EP detection of An X-ray Transient
  86. GRB 241213A: REM optical/NIR upper limits
  87. GRB 241213A: Enhanced Swift-XRT position
  88. GRB241212A: OHP/T193 optical observations
  89. GRB 241213A: SAO RAS optical upper limit
  90. GRB 241213A: Swift detection of a burst
  91. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  92. GRB 241209B: GRANDMA/TRT upper limit
  93. GRB 241212A: SVOM detection of a bright long burst
  94. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  95. GRB 241209D: REM optical/NIR upper limits
  96. GRB 241209B: Swift-XRT afterglow detection
  97. EP241208a: Optical upper limit with Kinder observations
  98. GRB 241209D: AstroSat CZTI detection
  99. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  100. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate

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