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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"

16215 results found.

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

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