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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').

17878 results found.

  1. GRB 241209D: REM optical/NIR upper limits
  2. Konus-Wind detection of GRB 241209D
  3. GRB 241209B: Swift-XRT afterglow detection
  4. GRB 241209C: Fermi GBM Observation
  5. GRB 241209A: Swift-XRT refined Analysis
  6. GRB 241209D: AstroSat CZTI detection
  7. GRB 241209A: EP-FXT follow-up observations
  8. GRB 241209B: SVOM/VT afterglow detection
  9. GRB 241207B: Fermi GBM Observation
  10. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  11. GRB 241209D: Swift-XRT refined Analysis
  12. GRB 241209D: Fermi GBM Observation
  13. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  14. GRB 241209D: COLIBRÍ detection of the afterglow
  15. GRB 241209A: COLIBRÍ Optical Upper Limit
  16. GRB 241209A: Fermi GBM Observation
  17. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  18. GRB 241209A: GRANDMA/TAROT upper limit
  19. Swift GRB 241209D: Global MASTER-Net observations report
  20. GRB 241209B: Swift ToO observations
  21. GRB 241209A: REM optical/NIR observations
  22. GRB 241209D: Enhanced Swift-XRT position
  23. GRB 241209D: Swift detection of a burst
  24. GRB 241209A: Enhanced Swift-XRT position
  25. GRB 241209A: GOTO optical upper limits
  26. GRB 241209A: Prompt enhanced Swift-XRT position
  27. GRB 241209A: Swift detection of a short burst
  28. Swift GRB241209.23: Global MASTER-Net observations report
  29. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  30. GRB 241206A: DDOTI Upper Limit on the Afterglow
  31. GRB 241207C: Tiled Swift observations
  32. GRB 241206A: Fermi GBM observation
  33. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  34. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  35. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  36. GRB 241128A: Swift/UVOT Upper Limits
  37. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  38. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  39. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  40. GRB 241128A: Swift-BAT refined analysis
  41. GRB 241127A: Swift-BAT refined analysis
  42. GRB 241127A: PRIME near-infrared detection
  43. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  44. Swift-XRT observations of IceCube -241127A
  45. Swift GRB 241128A: Global MASTER-Net observations report
  46. GRB 241128A: Swift-XRT refined Analysis
  47. GRB 241128A: Enhanced Swift-XRT position
  48. GRB 241128A: 1.5m OSN optical afterglow detection
  49. GRB 241128A: Swift-XRT afterglow detection
  50. GRB 241128A: Swift detection of a burst
  51. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  52. GRB 241127A: Swift/UVOT Detection
  53. GRB 241127A: Swift-XRT refined Analysis
  54. GRB 241127A: SVOM/GRM observation
  55. GRB 241127A: Enhanced Swift-XRT position
  56. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  57. Swift GRB241127.91: Global MASTER-Net OT detection
  58. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  59. GRB 241127A: Swift detection of a burst with an optical counterpart
  60. Swift GRB241127.91: Global MASTER-Net observations report
  61. Swift GRB241127.91: Global MASTER-Net OT detection
  62. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  63. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  64. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  65. IPN triangulation of GRB 241114B
  66. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  67. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  68. Trigger_18947: Swift ToO observations (retracted)
  69. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  70. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  71. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  72. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  73. EP241125a: EP detection of an X-ray transient
  74. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  75. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  76. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  77. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  78. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  79. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  80. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  81. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  82. Konus-Wind detection of GRB 241117A
  83. IPN triangulation of GRB 241117A
  84. GRB 241025A: VIRT Optical Upper Limit
  85. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 241115a: PRIME near-infrared upper limits
  87. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  88. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  89. GRB 241115B: Fermi GBM Observation
  90. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  91. GRB 241115C: Fermi GBM Observation
  92. GRB 241115A: Swift-XRT afterglow detection
  93. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  94. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  95. EP241113a: Swift XRT weak detection
  96. GRB 241115A: Fermi GBM Observation
  97. GRB 241115A: LCOGT Optical Upper Limits
  98. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  99. Swift GRB 241115A: Global MASTER-Net observations report
  100. GRB 241115A: Swift detection of a burst

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