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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"

16159 results found.

  1. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  2. GRB 241229A: SAO RAS optical observations
  3. GRB 241229B: SVOM/VT optical candidate
  4. EP240702a: 7DT Optical upper limits
  5. GRB 240606B: 7DT Optical upper limits
  6. GRB241229B: UVOT upper limits
  7. GRB 241228B: D50 optical detection
  8. GRB 241228B: Swift-XRT afterglow detection
  9. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  10. GRB 241228A: Mondy optical afterglow observations
  11. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  12. GRB 241229A: GOTO optical upper limits
  13. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  14. GRB 241228A: NOT optical upper limits
  15. GRB 241228B: LCO optical observation
  16. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  17. GRB241228B: GROWTH-India Telescope optical observations
  18. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  19. GRB 241228B: GOTO24jmz optical follow-up observations
  20. GRB 241228A: GROWTH-India telescope optical upper limit
  21. GRB 241228B: TRT optical counterpart confirmation
  22. GRB 241228A: Swift/UVOT Upper Limits
  23. GRB 241228B: GOTO possible optical counterpart candidate
  24. GRB 241217A/EP241217b: continued SOAR observations
  25. EP241223a: Mondy AZT-33IK optical observations
  26. GRB 241029A: LCO optical observation
  27. GRB 241223A: Swift-XRT observations
  28. GRB 241029A: AbAO AS-32 optical observations
  29. EP241223a
  30. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  31. GRB241113A: 7DT Optical upper limits
  32. GRB 241223A: GOTO optical observations summary
  33. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  34. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  35. GRB 241217A/EP241217b: SOAR afterglow detection
  36. EP241217a: Liverpool Telescope optical upper limit
  37. EP241021a: VLA radio detection
  38. GRB 241218A: Mondy AZT-33IK optical upper limit
  39. EP241217a : Leavitt Observatory optical upper limit
  40. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  41. EP241217a: 1.6m Mephisto multi-band optical observations
  42. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  43. GRB 241218A: Swift/UVOT Upper Limits
  44. EP241217a: optical upper limit with the Liverpool Telescope
  45. GRB 241209B: EP-FXT afterglow detection
  46. GRB 241218A: NOT optical upper limits
  47. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  48. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  49. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  50. GRB 241217A / EP241217b: NOT optical upper limits
  51. GRB 241218A: REM optical upper limit
  52. GRB 241217A/EP241217b: REM optical/NIR upper limits
  53. EP241217a: REM optical/NIR upper limits
  54. GRB 241218a: Liverpool Telescope optical follow-up
  55. GRB 241217a: Liverpool Telescope optical follow-up
  56. EP241217a: Liverpool Telescope optical follow-up
  57. EP241217a: NOT optical observations
  58. EP241217a: GROWTH-India Telescope optical observations
  59. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  60. EP241119a: 7DT Optical upper limits
  61. EP241217a: Xinglong optical follow-up observations
  62. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  63. GRB 241218A: LCOGT Optical Upper Limit
  64. GRB 241217A: GMG Optical Upper Limit
  65. GRB 241217A : SVOM/VT optical afterglow detection
  66. GRB 241217A: LCO optical upper limit
  67. GRB 241217A: GRANDMA/TAROT optical upperlimits
  68. EP241217a: Swift-XRT Detection
  69. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  70. EP241217a: Kinder optical follow-up observations
  71. EP241217A: LCO optical observations
  72. EP241217a: Gemini-North detection of the likely optical counterpart
  73. GRB 241215A: Mondy AZT-33IK optical observations
  74. GRB 241215A: Nanshan/HMT optical upper limit
  75. GRB 241215A: Montarrenti Observatory optical upper limit
  76. GRB 241215A: GROWTH-India telescope optical upper limit
  77. GRB 241209B: SVOM/VT optical continuous fading
  78. GRB 241213A: SVOM/VT optical candidate
  79. GRB 241213A: Swift/UVOT Upper Limits
  80. GRB 241212A: Fermi GBM detection
  81. EP241208a: NOT optical upper limits
  82. GRB 241213A: LCOGT Optical Upper Limits
  83. GRB 241213A: REM optical/NIR upper limits
  84. GRB241212A: OHP/T193 optical observations
  85. GRB 241213A: SAO RAS optical upper limit
  86. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  87. GRB 241212A : SVOM/VT bright optical afterglow
  88. GRB 241209B: GRANDMA/TRT upper limit
  89. GRB 241207A: TSHAO Zeiss-1000 optical observations
  90. GRB 241212A: SVOM detection of a bright long burst
  91. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  92. GRB 241209D: REM optical/NIR upper limits
  93. GRB 241209B: Swift-XRT afterglow detection
  94. EP241208a: Optical upper limit with Kinder observations
  95. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  96. GRB 241209B: SVOM/VT afterglow detection
  97. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  98. GRB 241209D: COLIBRÍ detection of the afterglow
  99. GRB 241209A: COLIBRÍ Optical Upper Limit
  100. GRB 241209A: Fermi GBM Observation

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