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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"

36161 results found.

  1. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  2. EP240919a / GRB 240919A: REM optical and NIR upper limits
  3. EP240919a / GRB 240919A: KAIT optical upper limit
  4. GRB 240414A: further radio observations with the VLA
  5. GRB 240919A / EP240919a: SVOM/GRM observation
  6. GRB 240910A: radio detection with the VLA
  7. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  8. EP240919a is likely a GRB event (duplicate submission of 37563)
  9. EP240919a is likely a GRB event
  10. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  11. GRB 240918B: Fermi GBM Detection
  12. GRB 240910A: further Swift observations and confirmation of afterglow
  13. Fermi GRB 240918A: Global MASTER-Net observations report
  14. GRB 240918A: Fermi GBM Final Real-time Localization
  15. EP240918a: YAHPT Optical Upper Limit
  16. GRB 240916A: GRBAlpha detection
  17. GRB 240914B: GRBAlpha detection
  18. GRB 240916A: NOT optical observation
  19. GRB 240912A: Swift-BAT refined analysis
  20. IPN triangulation of GRB 240913C / EP 240913a
  21. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  22. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  23. GRB 240916A: Fermi GBM Observation
  24. GRB 240821A: radio observation with the VLA
  25. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  26. GRB 240916A: Swift-XRT afterglow detection
  27. GRB 240916A: Swift ToO observations
  28. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  29. GRB 240916B: Fermi GBM Final Real-time Localization
  30. GRB 240914B: Fermi GBM Final Localization
  31. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  32. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  33. GRB 240916A: Fermi GBM Final Real-time Localization
  34. Fermi Gamma-ray Burst Monitor trigger 748124309/240915846 is not a GRB
  35. EP240913a/GRB 240913C: KAIT optical upper limit
  36. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  37. GRB 240913C: Fermi GBM detection
  38. GRB 240914A: Swift-XRT observations
  39. GRB 240913C: Joint location by ETJASMIN
  40. GRB 240914B: AstroSat CZTI detection
  41. EP240913A / GRB 240913C: AstroSat CZTI detection
  42. GRB 240914A: SVOM/GRM observation
  43. GRB 240910A: SVOM/VT optical observations
  44. GRB 240914A: Swift ToO observations
  45. EP240913a: ESO-NTT optical observations
  46. GRB 240914A: ESO-NTT optical observations
  47. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  48. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  49. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  50. GRB 240905E: further NOT optical observations
  51. EP240913a: A GRB Event
  52. GRB 240913B: Fermi GBM Final Real-time Localization
  53. GRB 240911A: LCO optical observations
  54. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  55. Fermi Gamma-ray Burst Monitor trigger 747837485/240912526 is not a GRB
  56. GRB 240912A: Swift/UVOT Detection
  57. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  58. GRB 240912A: SVOM/GRM observation
  59. GRB 240911A: Swift-XRT observations
  60. Fermi GRB 240913A: Global MASTER-Net observations report
  61. GRB 240913A: Fermi GBM Final Real-time Localization
  62. GRB 240912A: J-band observations with WINTER
  63. GRB 240912A: Swift-XRT refined Analysis
  64. GRB 240912A: Fermi GBM Observation
  65. Swift GRB 240912A: Global MASTER-Net observations report
  66. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  67. GRB 240911A: Tiled Swift observations
  68. Fermi Gamma-ray Burst Monitor trigger 747839931/240912555 is not a GRB
  69. GRB 240912A : INTEGRAL SPI ACS LIGHT CURVE
  70. GRB 240912B: Fermi GBM Final Real-time Localization
  71. GRB 240912A: NOT optical spectroscopy
  72. GRB 240912A: Enhanced Swift-XRT position
  73. GRB 240912A: Redshift from OSIRIS+/GTC
  74. GRB 240910A: Redshift from OSIRIS+/GTC
  75. GRB 240912A: Swift detection of a burst with an optical counterpart
  76. GRB 240912A: Fermi GBM Final Real-time Localization
  77. GRB 240910A: Fermi GBM Observation
  78. GRB 240910A: NOT optical observations
  79. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  80. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  81. GRB 240910A: JinShan optical observations
  82. GRB 240910A: GOTO candidate optical counterpart
  83. GRB 240710A: SVOM/GRM observation
  84. GRB 240910A: Swift ToO observations
  85. IPN triangulation of GRB 240905B (short)
  86. GRB 240825A: 7DT Optical Upper Limit
  87. GRB 240905E: SVOM/VT optical observations
  88. GRB 240905E: SVOM/VT optical observations (duplicate submission of GCN 37453)
  89. GRB 240910A: GRBAlpha detection
  90. GRB 240910B: Fermi GBM Final Real-time Localization
  91. GRB 240910A: SVOM/GRM observation
  92. EP240908a: Mondy and AbAO follow-up observations
  93. Fermi GRB 240910A: Global MASTER-Net observations report
  94. GRB 240910A: Fermi GBM Final Real-time Localization
  95. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  96. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  97. GRB 240905B: Fermi GBM Observation
  98. GRB 240905B: GOTO optical upper limits
  99. Fermi GRB 240908A: Global MASTER-Net observations report
  100. GRB 240908A: Fermi GBM Final Real-time Localization

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