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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"

6792 results found.

  1. GRB 241228B: TRT optical counterpart confirmation
  2. GRB 241228A: Swift-XRT refined Analysis
  3. GRB 241223A: Swift-XRT observations
  4. GRB 241223A: Fermi GBM Detection
  5. GRB241113A: 7DT Optical upper limits
  6. GRB 241218A: NOT optical upper limits
  7. EP 241217a: NIR detection with P200/WIRC
  8. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  9. GRB 241218A: Swift-XRT refined Analysis
  10. EP241119a: 7DT Optical upper limits
  11. GRB 241217A : SVOM/VT optical afterglow detection
  12. GRB 241217A: Swift-XRT afterglow detection
  13. EP241217a: Swift-XRT Detection
  14. EP241217a: Kinder optical follow-up observations
  15. GRB 241212A: Swift-XRT observations
  16. GRB 241213B: Swift-XRT observations
  17. GRB 241213A: Swift-XRT refined Analysis
  18. GRB 241212A: Fermi GBM detection
  19. EP241213a: EP detection of An X-ray Transient
  20. GRB 241213A: SAO RAS optical upper limit
  21. GRB 241209A: Chandra X-ray Detection
  22. GRB 241129A: Fermi GBM Observation
  23. Konus-Wind detection of GRB 241209D
  24. GRB 241209B: Swift-XRT afterglow detection
  25. GRB 241209C: Fermi GBM Observation
  26. GRB 241209A: Swift-XRT refined Analysis
  27. EP241208a: Optical upper limit with Kinder observations
  28. EP241208a: EP-FXT follow-up observations
  29. GRB 241207B: Fermi GBM Observation
  30. GRB 241209D: Swift-XRT refined Analysis
  31. GRB 241209D: Fermi GBM Observation
  32. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  33. GRB 241209A: Fermi GBM Observation
  34. EP241206a: 1.5m OSN optical limit
  35. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  36. GRB 241206A: Fermi GBM observation
  37. EP241201a: 1.6m Mephisto Optical Upper Limits
  38. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  39. GRB 241204A: Fermi GBM Observation
  40. Fermi GRB 241204A: Global MASTER-Net observations report
  41. GRB 241204A: Fermi-LAT detection
  42. EP241202b: Kinder optical counterpart candidate
  43. EP241201a: EP-FXT follow-up observations
  44. GRB 241130A: Fermi GBM Detection
  45. EP241201a: Kinder optical counterpart candidate
  46. Swift-XRT observations of IceCube -241127A
  47. Fermi-LAT gamma-ray observations of IceCube-241127A
  48. GRB 241128A: Swift-XRT refined Analysis
  49. GRB 241128A: Swift-XRT afterglow detection
  50. GRB 241127A: Swift-XRT refined Analysis
  51. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  52. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  53. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  54. EP241126a: Optical Upper limits with Kinder observations
  55. EP241126a: TRT optical counterpart detection
  56. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  57. Konus-Wind detection of GRB 241115D / EP 241115a
  58. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  59. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  60. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  61. EP241119a: Optical upper limits with Kinder observations
  62. EP241119a: GIT optical upper limits
  63. GRB 241120A: Fermi GBM Observation
  64. GRB 241112B: Mephisto further optical observations
  65. GRB 241115B: Fermi GBM Observation
  66. GRB 241117A: Fermi GBM Detection
  67. GRB 241115C: Fermi GBM Observation
  68. GRB 241115A: Swift-XRT afterglow detection
  69. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  70. GRB 241113B: Mephisto upper limits
  71. GRB 241115A: Fermi GBM Observation
  72. GRB 241030A: LCO optical observation
  73. GRB 241113B: Swift-XRT observations
  74. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  75. Fermi-LAT gamma-ray observations of IceCube-241113A
  76. GRB 241113A: Swift-XRT refined Analysis
  77. GRB 241112B: Swift-XRT afterglow detection
  78. GRB 241108A: Swift-XRT observations
  79. EP241107a: Kinder optical follow-up observations
  80. EP241107a: GIT optical observations
  81. GRB 241105A: Swift/UVOT Detection
  82. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  83. Konus-Wind detection of GRB 241105A (short with extended emission)
  84. GRB 241105A: Swift-XRT afterglow detection
  85. GRB 241104A: Swift-XRT observations
  86. GRB 241104A: Fermi GBM Observation
  87. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  88. EP241104a: EP detection of GRB 241104A X-ray emission
  89. EP241101a: EP-FXT observations update
  90. EP241103a: GIT optical upper limit
  91. EP241101a: Optical upper limits with Kinder observations
  92. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  93. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  94. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  95. EP241101a: EP-WXT detection of a fast X-ray transient
  96. EP241021a: Upper limit from Konus-Wind observations
  97. GRB 241030A: Optical Observations via Virtual Telescope Project
  98. GRB 241030B: Swift-XRT refined Analysis
  99. GRB 241030A: SAO RAS optical observations
  100. GRB 241030A: Fermi GBM Observation

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