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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

45772 results found.

  1. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  2. Konus-Wind detection of GRB 240926A
  3. GRB 241002B: PRIME near-infrared detection
  4. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  5. GRB 241002C: Swift ToO observations
  6. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  7. IPN triangulation of GRB 240930B / EP 240930a
  8. GRB 241001A : SVOM/VT optical detection
  9. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  10. GRB 241002D: SVOM/GRM observation
  11. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  12. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  13. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  14. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  15. GRB 241002C : MITSuME Akeno optical upper limits
  16. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  17. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  18. GRB241001A: REM optical/NIR upper limits
  19. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  20. GRB 241002A: Swift/UVOT Upper Limits
  21. EP240930a: Liverpool Telescope observations
  22. GRB 241002A: Swift-XRT refined Analysis
  23. GRB 241002A: LCOGT Optical Upper Limits
  24. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  25. GRB 241001A: Swift/UVOT Detection
  26. GRB 241001A: VLT/X-shooter redshift
  27. GRB 241002B: GOTO optical counterpart candidate
  28. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  29. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  30. GRB 241001A: correction to GCN 37667
  31. Fermi GRB 241002B: Global MASTER-Net observations report
  32. GRB 241001A: Swift-XRT observations
  33. EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
  34. GRB 241002B: Fermi GBM Final Real-time Localization
  35. GRB241001A: optical afterglow candidate
  36. GRB 241002A: 1.5m OSN optical upper limit
  37. GRB 241002A: Enhanced Swift-XRT position
  38. GRB 241001A: BOOTES-6/DPRT optical upper limit
  39. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  40. GRB 241002A: Swift detection of a burst
  41. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  42. GRB 240930B: Fermi GBM Observation
  43. GRB 241001A: Swift ToO observations
  44. GRB 240930B: GRBAlpha detection
  45. GRB 240929A: GRBAlpha detection
  46. EP240930a : KAIT optical upper limit
  47. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  48. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  49. EP240930a: EP-FXT follow-up observation update
  50. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  51. EP240930a: GOTO optical upper limits
  52. GRB 240929A: SVOM/GRM observation
  53. EP EP240930a: Global MASTER-Net observations report
  54. EP240930a: EP-WXT detection of a fast X-ray transient
  55. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  56. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  57. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  58. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  59. AMON NuEM 240926A: Swift XRT Follow-up
  60. GRB 240929A : Leavitt Observatory optical upper limit
  61. Fermi GRB 240930B: Global MASTER-Net observations report
  62. GRB 240930B: Fermi GBM Final Real-time Localization
  63. IPN triangulation of GRB 240926A
  64. GRB 240825A: LBT optical observations
  65. GRB 240928A: SVOM/GRM observation
  66. Fermi GRB 240930A: Global MASTER-Net observations report
  67. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  68. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  69. GRB 240930A: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 749339671: Global MASTER-Net observations report
  71. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  72. GRB 240929A long GRB detected by INTEGRAL
  73. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  74. Fermi GRB 240929A: Global MASTER-Net observations report
  75. GRB 240929A: Fermi GBM Final Real-time Localization
  76. Integral GRB240929.83: Global MASTER-Net observations report
  77. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  78. Konus-Wind detection of GRB 240912A
  79. Swift Trigger 1256950 is probably not a GRB
  80. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  81. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  82. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  83. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  84. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  85. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  86. GRB 240926A: SVOM/GRM observation
  87. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  88. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  89. Konus-Wind detection of GRB 240905B
  90. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  91. GW S240915b and S240919bn : Swift UVOT follow-up
  92. EP240919a / GRB 240919A: SVOM/VT upper limit
  93. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  94. EP240918b and EP240918c: EP-FXT follow-up observations
  95. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  96. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  97. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  98. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  99. Konus-Wind detection of GRB 240918B
  100. IPN triangulation of GRB 240918B

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