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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"

15722 results found.

  1. GRB 241218A: Mondy AZT-33IK optical upper limit
  2. EP241217a : Leavitt Observatory optical upper limit
  3. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  4. EP241217a: 1.6m Mephisto multi-band optical observations
  5. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  6. GRB 241218A: Swift/UVOT Upper Limits
  7. EP241217a: optical upper limit with the Liverpool Telescope
  8. GRB 241209B: EP-FXT afterglow detection
  9. GRB 241218A: NOT optical upper limits
  10. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  11. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  12. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  13. GRB 241217A / EP241217b: NOT optical upper limits
  14. GRB 241218A: REM optical upper limit
  15. GRB 241217A/EP241217b: REM optical/NIR upper limits
  16. EP241217a: REM optical/NIR upper limits
  17. GRB 241218a: Liverpool Telescope optical follow-up
  18. GRB 241217a: Liverpool Telescope optical follow-up
  19. EP241217a: Liverpool Telescope optical follow-up
  20. EP241217a: NOT optical observations
  21. EP241217a: GROWTH-India Telescope optical observations
  22. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  23. EP241119a: 7DT Optical upper limits
  24. EP241217a: Xinglong optical follow-up observations
  25. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  26. GRB 241218A: LCOGT Optical Upper Limit
  27. GRB 241217A: GMG Optical Upper Limit
  28. GRB 241217A : SVOM/VT optical afterglow detection
  29. GRB 241217A: LCO optical upper limit
  30. GRB 241217A: GRANDMA/TAROT optical upperlimits
  31. EP241217a: Swift-XRT Detection
  32. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  33. EP241217a: Kinder optical follow-up observations
  34. EP241217A: LCO optical observations
  35. EP241217a: Gemini-North detection of the likely optical counterpart
  36. GRB 241215A: Mondy AZT-33IK optical observations
  37. GRB 241215A: Nanshan/HMT optical upper limit
  38. GRB 241215A: Montarrenti Observatory optical upper limit
  39. GRB 241215A: GROWTH-India telescope optical upper limit
  40. GRB 241209B: SVOM/VT optical continuous fading
  41. GRB 241213A: SVOM/VT optical candidate
  42. GRB 241213A: Swift/UVOT Upper Limits
  43. GRB 241212A: Fermi GBM detection
  44. EP241208a: NOT optical upper limits
  45. GRB 241213A: LCOGT Optical Upper Limits
  46. GRB 241213A: REM optical/NIR upper limits
  47. GRB241212A: OHP/T193 optical observations
  48. GRB 241213A: SAO RAS optical upper limit
  49. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  50. GRB 241212A : SVOM/VT bright optical afterglow
  51. GRB 241209B: GRANDMA/TRT upper limit
  52. GRB 241207A: TSHAO Zeiss-1000 optical observations
  53. GRB 241212A: SVOM detection of a bright long burst
  54. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  55. GRB 241209D: REM optical/NIR upper limits
  56. GRB 241209B: Swift-XRT afterglow detection
  57. EP241208a: Optical upper limit with Kinder observations
  58. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  59. GRB 241209B: SVOM/VT afterglow detection
  60. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  61. GRB 241209D: COLIBRÍ detection of the afterglow
  62. GRB 241209A: COLIBRÍ Optical Upper Limit
  63. GRB 241209A: Fermi GBM Observation
  64. GRB 241209A: GRANDMA/TAROT upper limit
  65. GRB 241209B: BOOTES-5 optical upper limit
  66. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  67. GRB 241209A: REM optical/NIR observations
  68. GRB 241209D: Swift detection of a burst
  69. GRB 241209A: VLT optical observations
  70. GRB 241209A: GOTO optical upper limits
  71. EP241206a: 1.5m OSN optical limit
  72. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  73. EP241206a: BOOTES Global Network optical limits
  74. GRB 241207C: MASTER optical observations
  75. GRB 241206B: GWAC-F50A optical upper limit
  76. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  77. EP241201a: 1.6m Mephisto Optical Upper Limits
  78. GRB 241204A: COLIBRÍ Optical Upper Limit
  79. EP241202b: KAIT optical upper limit
  80. EP241202b: Kinder optical counterpart candidate
  81. EP241201a: BOOTES-5 optical upper limit
  82. EP241201a: NOT optical observations
  83. GRB 241128A: Swift/UVOT Upper Limits
  84. EP241201a: Kinder optical counterpart candidate
  85. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  86. EP241126a: SOAR observations of the optical counterpart
  87. EP241126a: 1.6m Mephisto Optical Upper Limits
  88. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  89. GRB 241128A: AbAO optical upper limit
  90. EP241126a: NOT optical observations
  91. GRB 241127A: PRIME near-infrared detection
  92. GRB 241128A: Mondy optical observations
  93. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  94. Swift-XRT observations of IceCube -241127A
  95. EP241126a: SVOM/VT observations
  96. GRB 241128A: NOT optical observations
  97. GRB 241128A: LCO optical detection
  98. GRB 241128A: 1.5m OSN optical afterglow detection
  99. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  100. GRB 241127A: Swift/UVOT Detection

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