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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').
  1. EP241217a: 1.6m Mephisto multi-band optical observations
  2. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  3. GRB 241218A: Swift/UVOT Upper Limits
  4. EP241217a: optical upper limit with the Liverpool Telescope
  5. GRB 241209B: EP-FXT afterglow detection
  6. Konus-Wind detection of GRB 241204A (short/hard)
  7. GRB 241218A: NOT optical upper limits
  8. GRB 241218A: Swift-BAT refined analysis
  9. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  10. EP 241217a: NIR detection with P200/WIRC
  11. EP 241217a: Possible J-band detection with WINTER
  12. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  13. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  14. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  15. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  16. GRB 241217A / EP241217b: NOT optical upper limits
  17. GRB 241218A: REM optical upper limit
  18. GRB 241217A/EP241217b: REM optical/NIR upper limits
  19. EP241217a: REM optical/NIR upper limits
  20. GRB 241218a: Liverpool Telescope optical follow-up
  21. GRB 241217a: Liverpool Telescope optical follow-up
  22. EP241217a: Liverpool Telescope optical follow-up
  23. GRB 241218A: Swift-XRT refined Analysis
  24. EP241217a: NOT optical observations
  25. EP241217a: GROWTH-India Telescope optical observations
  26. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  27. EP241119a: 7DT Optical upper limits
  28. EP241217b: Global MASTER-Net observations report
  29. GRB 241209A: ATCA radio follow-up observations
  30. EP241217a: Xinglong optical follow-up observations
  31. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  32. GRB 241218A: LCOGT Optical Upper Limit
  33. GRB 241218A: Enhanced Swift-XRT position
  34. EP241217a: Global MASTER-Net observations report
  35. GRB 241217A: GMG Optical Upper Limit
  36. GRB 241218A: Swift detection of a burst
  37. GRB 241217A : SVOM/VT optical afterglow detection
  38. GRB 241217A: Swift-XRT afterglow detection
  39. GRB 241217A: LCO optical upper limit
  40. GRB 241217A: GRANDMA/TAROT optical upperlimits
  41. EP241217a: Swift-XRT Detection
  42. EP241217A: Non-detection from Fermi-GBM Observations
  43. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  44. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  45. EP241217a: Kinder optical follow-up observations
  46. GRB 241214A: GRBAlpha detection
  47. GRB 241213A (EP241213a): GRBAlpha detection
  48. GRB 241209D: GRBAlpha detection
  49. EP241217A: LCO optical observations
  50. EP241217a: Gemini-North detection of the likely optical counterpart
  51. EP241217a: EP detection of an X-ray transient
  52. The EP-WXT trigger 01709129023 is likely a flaring star
  53. EP241107a: VLA Radio Observation
  54. GRB 241213A: Swift-BAT refined analysis
  55. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  56. Konus-Wind detection of GRB 241213A (EP 241213a)
  57. GRB 241215A: Mondy AZT-33IK optical observations
  58. GRB 241212A: Swift-XRT observations
  59. GRB 241214A: SVOM/GRM observation
  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. GRB 241215A: A long GRB detected by INTEGRAL
  65. Integral GRB241215.58: Global MASTER-Net observations report
  66. The EP-WXT trigger 01709128921 is likely a flaring star
  67. GRB 241213B: Swift-XRT observations
  68. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  69. GRB 241209B: SVOM/VT optical continuous fading
  70. EP trigger ID 01709128824 is not a real source
  71. GRB 241213A: SVOM/VT optical candidate
  72. GRB 241213B: Tiled Swift observations
  73. GRB 241213A: Swift/UVOT Upper Limits
  74. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  75. GRB 241213A: Swift-XRT refined Analysis
  76. GRB 241212A: Fermi GBM detection
  77. EP241208a: NOT optical upper limits
  78. GRB 241212A: Swift ToO observations
  79. GRB 241213A: LCOGT Optical Upper Limits
  80. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  81. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  82. GRB 241213B: MAXI/GSC detection
  83. EP241213a: EP detection of An X-ray Transient
  84. GRB 241213A: REM optical/NIR upper limits
  85. GRB 241213A: Enhanced Swift-XRT position
  86. GRB241212A: OHP/T193 optical observations
  87. GRB 241213A: SAO RAS optical upper limit
  88. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  89. Swift GRB 241213A: Global MASTER-Net observations report
  90. GRB 241213A: Swift detection of a burst
  91. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  92. GRB 241212A : SVOM/VT bright optical afterglow
  93. GRB 241212A: AstroSat CZTI detection
  94. GRB 241209B: GRANDMA/TRT upper limit
  95. GRB 241207A: TSHAO Zeiss-1000 optical observations
  96. GRB 241212A: SVOM detection of a bright long burst
  97. GRB 241212A: Fermi GBM Final Real-time Localization
  98. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  99. GRB 241209A: Chandra X-ray Detection
  100. Konus-Wind detection of GRB 241209B

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