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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"

35427 results found.

  1. GRB 241002C : MITSuME Akeno optical upper limits
  2. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  3. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  4. GRB241001A: REM optical/NIR upper limits
  5. GRB 241002A: Swift/UVOT Upper Limits
  6. GRB 241002A: Swift-XRT refined Analysis
  7. GRB 241002A: LCOGT Optical Upper Limits
  8. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  9. GRB 241001A: Swift/UVOT Detection
  10. GRB 241001A: VLT/X-shooter redshift
  11. GRB 241002B: GOTO optical counterpart candidate
  12. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  13. GRB 241001A: correction to GCN 37667
  14. GRB 240929A: Liverpool Telescope prompt followup observations
  15. Fermi GRB 241002B: Global MASTER-Net observations report
  16. GRB 241001A: Swift-XRT observations
  17. GRB 241002B: Fermi GBM Final Real-time Localization
  18. GRB241001A: optical afterglow candidate
  19. GRB 241002A: 1.5m OSN optical upper limit
  20. GRB 241002A: Enhanced Swift-XRT position
  21. GRB 241001A: BOOTES-6/DPRT optical upper limit
  22. GRB 241002A: Swift detection of a burst
  23. GRB 240930B: Fermi GBM Observation
  24. GRB 241001A: Swift ToO observations
  25. GRB 240930B: GRBAlpha detection
  26. GRB 240929A: GRBAlpha detection
  27. EP240930a : KAIT optical upper limit
  28. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  29. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  30. EP240930a: EP-FXT follow-up observation update
  31. EP240930a: GOTO optical upper limits
  32. GRB 240929A: SVOM/GRM observation
  33. EP240930a: EP-WXT detection of a fast X-ray transient
  34. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 240929A : Leavitt Observatory optical upper limit
  36. Fermi GRB 240930B: Global MASTER-Net observations report
  37. GRB 240930B: Fermi GBM Final Real-time Localization
  38. IPN triangulation of GRB 240926A
  39. GRB 240825A: LBT optical observations
  40. GRB 240928A: SVOM/GRM observation
  41. Fermi GRB 240930A: Global MASTER-Net observations report
  42. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  43. GRB 240930A: Fermi GBM Final Real-time Localization
  44. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  45. GRB 240929A long GRB detected by INTEGRAL
  46. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  47. Fermi GRB 240929A: Global MASTER-Net observations report
  48. GRB 240929A: Fermi GBM Final Real-time Localization
  49. Konus-Wind detection of GRB 240912A
  50. Swift Trigger 1256950 is probably not a GRB
  51. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  52. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  54. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  55. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  56. GRB 240926A: SVOM/GRM observation
  57. Konus-Wind detection of GRB 240905B
  58. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  59. EP240919a / GRB 240919A: SVOM/VT upper limit
  60. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  61. Konus-Wind detection of GRB 240918B
  62. IPN triangulation of GRB 240918B
  63. GRB 240905B: VZLUSAT-2 detection
  64. GRB 240918B: AstroSat CZTI detection
  65. EP240913A/GRB 240913C: AbAO optical upper limit
  66. EP240919a / GRB 240919A: Mondy optical upper limit
  67. EP240913a/GRB 240913C: 1.6m Mephisto observations
  68. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  69. EP240919a / GRB 240919A: REM optical and NIR upper limits
  70. EP240919a / GRB 240919A: KAIT optical upper limit
  71. GRB 240414A: further radio observations with the VLA
  72. GRB 240919A / EP240919a: SVOM/GRM observation
  73. GRB 240910A: radio detection with the VLA
  74. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  75. EP240919a is likely a GRB event (duplicate submission of 37563)
  76. EP240919a is likely a GRB event
  77. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  78. GRB 240918B: Fermi GBM Detection
  79. GRB 240910A: further Swift observations and confirmation of afterglow
  80. Fermi GRB 240918A: Global MASTER-Net observations report
  81. GRB 240918A: Fermi GBM Final Real-time Localization
  82. EP240918a: YAHPT Optical Upper Limit
  83. GRB 240916A: GRBAlpha detection
  84. GRB 240914B: GRBAlpha detection
  85. GRB 240916A: NOT optical observation
  86. GRB 240912A: Swift-BAT refined analysis
  87. IPN triangulation of GRB 240913C / EP 240913a
  88. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  89. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  90. GRB 240916A: Fermi GBM Observation
  91. GRB 240821A: radio observation with the VLA
  92. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  93. GRB 240916A: Swift-XRT afterglow detection
  94. GRB 240916A: Swift ToO observations
  95. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  96. GRB 240916B: Fermi GBM Final Real-time Localization
  97. GRB 240914B: Fermi GBM Final Localization
  98. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  99. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  100. GRB 240916A: Fermi GBM Final Real-time Localization

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