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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"

45431 results found.

  1. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  2. GRB 241209B: SVOM/VT optical continuous fading
  3. EP trigger ID 01709128824 is not a real source
  4. GRB 241213A: SVOM/VT optical candidate
  5. GRB 241213B: Tiled Swift observations
  6. GRB 241213A: Swift/UVOT Upper Limits
  7. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  8. GRB 241213A: Swift-XRT refined Analysis
  9. GRB 241212A: Fermi GBM detection
  10. EP241208a: NOT optical upper limits
  11. GRB 241212A: Swift ToO observations
  12. GRB 241213A: LCOGT Optical Upper Limits
  13. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  14. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  15. GRB 241213B: MAXI/GSC detection
  16. EP241213a: EP detection of An X-ray Transient
  17. GRB 241213A: REM optical/NIR upper limits
  18. GRB 241213A: Enhanced Swift-XRT position
  19. GRB241212A: OHP/T193 optical observations
  20. GRB 241213A: SAO RAS optical upper limit
  21. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  22. Swift GRB 241213A: Global MASTER-Net observations report
  23. GRB 241213A: Swift detection of a burst
  24. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  25. GRB 241212A : SVOM/VT bright optical afterglow
  26. GRB 241212A: AstroSat CZTI detection
  27. GRB 241209B: GRANDMA/TRT upper limit
  28. GRB 241207A: TSHAO Zeiss-1000 optical observations
  29. GRB 241212A: SVOM detection of a bright long burst
  30. GRB 241212A: Fermi GBM Final Real-time Localization
  31. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  32. GRB 241209A: Chandra X-ray Detection
  33. Konus-Wind detection of GRB 241209B
  34. GRB 241207A: EIRSAT-1 GMOD Detection
  35. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  36. GRB 241209B: GRBAlpha detection
  37. GRB 241206C: GRBAlpha detection
  38. LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
  39. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  40. GRB 241211A: Fermi GBM Final Real-time Localization
  41. GRB 241129A: Fermi GBM Observation
  42. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  43. GRB 241209D: REM optical/NIR upper limits
  44. Konus-Wind detection of GRB 241209D
  45. GRB 241209B: Swift-XRT afterglow detection
  46. GRB 241209C: Fermi GBM Observation
  47. GRB 241209A: Swift-XRT refined Analysis
  48. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  49. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  50. EP241208a: Optical upper limit with Kinder observations
  51. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  52. GRB 241209D: AstroSat CZTI detection
  53. GRB 241209A: EP-FXT follow-up observations
  54. GRB 241209B: SVOM/VT afterglow detection
  55. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  56. EP241208a: Global MASTER-Net observations report
  57. EP241208a: EP-FXT follow-up observations
  58. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  59. Fermi trigger No 755485387: Global MASTER-Net observations report
  60. GRB 241207B: Fermi GBM Observation
  61. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  62. GRB 241209D: Swift-XRT refined Analysis
  63. GRB 241209D: Fermi GBM Observation
  64. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  65. GRB 241209D: COLIBRÍ detection of the afterglow
  66. GRB 241209A: COLIBRÍ Optical Upper Limit
  67. Fermi GRB 241209D: Global MASTER-Net observations report
  68. GRB 241209A: Fermi GBM Observation
  69. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  70. GRB 241209A: GRANDMA/TAROT upper limit
  71. GRB 241209B: BOOTES-5 optical upper limit
  72. Swift GRB 241209D: Global MASTER-Net observations report
  73. Fermi GRB 241209C: Global MASTER-Net observations report
  74. Fermi GRB 241209E: Global MASTER-Net observations report
  75. GRB 241209E: Fermi GBM Final Real-time Localization
  76. GRB 241209B: Swift ToO observations
  77. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  78. GRB 241209A: REM optical/NIR observations
  79. GRB 241209D: Enhanced Swift-XRT position
  80. GRB 241209C: AstroSat CZTI detection
  81. GRB 241209D: Swift detection of a burst
  82. GRB 241209D: Fermi GBM Final Real-time Localization
  83. GRB 241209A: VLT/X-shooter spectroscopy
  84. GRB 241209A: Enhanced Swift-XRT position
  85. GRB 241114B: cubesat Avion detection
  86. GRB 241209A: VLT optical observations
  87. Fermi GRB 241209A: Global MASTER-Net observations report
  88. GRB 241209C: Fermi GBM Final Real-time Localization
  89. GRB 241209A: GOTO optical upper limits
  90. EP241206a: 1.5m OSN optical limit
  91. GRB 241209A: Prompt enhanced Swift-XRT position
  92. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  93. EP241208a: EP detection of a fast X-ray transient
  94. GRB 241209A: Swift detection of a short burst
  95. Swift GRB241209.23: Global MASTER-Net observations report
  96. GRB 241209A: Fermi GBM Final Real-time Localization
  97. Fermi GRB 241207B: Global MASTER-Net observations report
  98. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  99. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  100. GRB 241201A: AstroSat CZTI detection

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