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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"

6667 results found.

  1. GRB 241209A: Swift-XRT refined Analysis
  2. EP241208a: Optical upper limit with Kinder observations
  3. EP241208a: EP-FXT follow-up observations
  4. GRB 241207B: Fermi GBM Observation
  5. GRB 241209D: Swift-XRT refined Analysis
  6. GRB 241209D: Fermi GBM Observation
  7. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  8. GRB 241209A: Fermi GBM Observation
  9. EP241206a: 1.5m OSN optical limit
  10. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  11. GRB 241206A: Fermi GBM observation
  12. EP241201a: 1.6m Mephisto Optical Upper Limits
  13. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  14. GRB 241204A: Fermi GBM Observation
  15. Fermi GRB 241204A: Global MASTER-Net observations report
  16. GRB 241204A: Fermi-LAT detection
  17. EP241202b: Kinder optical counterpart candidate
  18. EP241201a: EP-FXT follow-up observations
  19. GRB 241130A: Fermi GBM Detection
  20. EP241201a: Kinder optical counterpart candidate
  21. Swift-XRT observations of IceCube -241127A
  22. Fermi-LAT gamma-ray observations of IceCube-241127A
  23. GRB 241128A: Swift-XRT refined Analysis
  24. GRB 241128A: Swift-XRT afterglow detection
  25. GRB 241127A: Swift-XRT refined Analysis
  26. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  27. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  28. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  29. EP241126a: Optical Upper limits with Kinder observations
  30. EP241126a: TRT optical counterpart detection
  31. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  32. Konus-Wind detection of GRB 241115D / EP 241115a
  33. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  34. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  35. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  36. EP241119a: Optical upper limits with Kinder observations
  37. EP241119a: GIT optical upper limits
  38. GRB 241120A: Fermi GBM Observation
  39. GRB 241112B: Mephisto further optical observations
  40. GRB 241115B: Fermi GBM Observation
  41. GRB 241117A: Fermi GBM Detection
  42. GRB 241115C: Fermi GBM Observation
  43. GRB 241115A: Swift-XRT afterglow detection
  44. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  45. GRB 241113B: Mephisto upper limits
  46. GRB 241115A: Fermi GBM Observation
  47. GRB 241030A: LCO optical observation
  48. GRB 241113B: Swift-XRT observations
  49. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  50. Fermi-LAT gamma-ray observations of IceCube-241113A
  51. GRB 241113A: Swift-XRT refined Analysis
  52. GRB 241112B: Swift-XRT afterglow detection
  53. GRB 241108A: Swift-XRT observations
  54. EP241107a: Kinder optical follow-up observations
  55. EP241107a: GIT optical observations
  56. GRB 241105A: Swift/UVOT Detection
  57. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  58. Konus-Wind detection of GRB 241105A (short with extended emission)
  59. GRB 241105A: Swift-XRT afterglow detection
  60. GRB 241104A: Swift-XRT observations
  61. GRB 241104A: Fermi GBM Observation
  62. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  63. EP241104a: EP detection of GRB 241104A X-ray emission
  64. EP241101a: EP-FXT observations update
  65. EP241103a: GIT optical upper limit
  66. EP241101a: Optical upper limits with Kinder observations
  67. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  68. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  69. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  70. EP241101a: EP-WXT detection of a fast X-ray transient
  71. EP241021a: Upper limit from Konus-Wind observations
  72. GRB 241030A: Optical Observations via Virtual Telescope Project
  73. GRB 241030B: Swift-XRT refined Analysis
  74. GRB 241030A: SAO RAS optical observations
  75. GRB 241030A: Fermi GBM Observation
  76. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  77. GRB241030B: Fermi GBM Observation
  78. GRB 241029A: SVOM/VT optical afterglow observations
  79. EP241021a: Swift-UVOT detection
  80. GRB 241030A: Swift-XRT refined Analysis
  81. GRB 241030B: SAO RAS optical observations
  82. Konus-Wind detection of GRB 241030A
  83. GRB 241030A: Fermi-LAT detection
  84. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  85. GRB 241029A: SAO RAS optical observations
  86. EP241021a: SAO RAS observations of rebrightening
  87. GRB 241029A: Swift-XRT observations
  88. GRB 241029A: Fermi GBM Observation
  89. Konus-Wind detection of GRB 241025A
  90. GRB 241025A: further SAO RAS optical observations
  91. GRB 241026A: BTA and Zeiss-1000 optical observations
  92. GRB 241026A Fermi GBM Analysis
  93. GRB 241025A: SAO RAS optical observations
  94. EP241021a: further SAO RAS optical observations
  95. GRB 241026A: Swift-XRT refined Analysis
  96. GRB241025A: 1.3m DFOT optical afterglow detection
  97. ​GRB 241025A: optical photometry from Konkoly
  98. GRB 241025A: Swift-XRT refined Analysis
  99. GRB 241025C: Fermi GBM Detection
  100. GRB 241025A: Fermi GBM Observation

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