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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"

43157 results found.

  1. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  2. IceCube Alert 241006.94: Global MASTER-Net observations report
  3. GRB 241001A: Swift-XRT afterglow detection
  4. GRB 241006A: Enhanced Swift-XRT position
  5. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 241006A: Swift detection of a burst
  7. Swift GRB241006.91: Global MASTER-Net observations report
  8. GRB 240930B: SVOM/C-GFT optical upper limit
  9. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S241005bo: Retraction of GW compact binary merger candidate
  11. Fermi trigger No 749721670: Global MASTER-Net observations report
  12. GRB 241004A: SVOM/GRM observation
  13. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  14. GRB 240930B / EP 240930a: SVOM/GRM observation
  15. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  16. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  17. GRB 241002B: Fermi GBM Observation
  18. Fermi trigger No 749735279: Global MASTER-Net observations report
  19. Fermi trigger No 749630753: Global MASTER-Net observations report
  20. Fermi trigger No 749693019: Global MASTER-Net observations report
  21. GRB 241002B: Swift-XRT observations
  22. GRB 241002C: SVOM/C-GFT optical upper limit
  23. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  24. GRB 241002B: Swift ToO observations
  25. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  26. Konus-Wind detection of GRB 240926A
  27. GRB 241002B: PRIME near-infrared detection
  28. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  29. GRB 241002C: Swift ToO observations
  30. IPN triangulation of GRB 240930B / EP 240930a
  31. GRB 241001A : SVOM/VT optical detection
  32. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  33. GRB 241002D: SVOM/GRM observation
  34. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  35. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  36. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  37. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  38. GRB 241002C : MITSuME Akeno optical upper limits
  39. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  40. GRB241001A: REM optical/NIR upper limits
  41. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  42. GRB 241002A: Swift/UVOT Upper Limits
  43. EP240930a: Liverpool Telescope observations
  44. GRB 241002A: Swift-XRT refined Analysis
  45. GRB 241002A: LCOGT Optical Upper Limits
  46. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  47. GRB 241001A: Swift/UVOT Detection
  48. GRB 241001A: VLT/X-shooter redshift
  49. GRB 241002B: GOTO optical counterpart candidate
  50. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  51. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  52. GRB 241001A: correction to GCN 37667
  53. Fermi GRB 241002B: Global MASTER-Net observations report
  54. GRB 241001A: Swift-XRT observations
  55. EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
  56. GRB 241002B: Fermi GBM Final Real-time Localization
  57. GRB241001A: optical afterglow candidate
  58. GRB 241002A: 1.5m OSN optical upper limit
  59. GRB 241002A: Enhanced Swift-XRT position
  60. GRB 241001A: BOOTES-6/DPRT optical upper limit
  61. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  62. GRB 241002A: Swift detection of a burst
  63. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  64. GRB 240930B: Fermi GBM Observation
  65. GRB 241001A: Swift ToO observations
  66. GRB 240930B: GRBAlpha detection
  67. GRB 240929A: GRBAlpha detection
  68. EP240930a : KAIT optical upper limit
  69. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  70. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  71. EP240930a: EP-FXT follow-up observation update
  72. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  73. EP240930a: GOTO optical upper limits
  74. GRB 240929A: SVOM/GRM observation
  75. EP EP240930a: Global MASTER-Net observations report
  76. EP240930a: EP-WXT detection of a fast X-ray transient
  77. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  78. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  79. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  80. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  81. GRB 240929A : Leavitt Observatory optical upper limit
  82. Fermi GRB 240930B: Global MASTER-Net observations report
  83. GRB 240930B: Fermi GBM Final Real-time Localization
  84. IPN triangulation of GRB 240926A
  85. GRB 240825A: LBT optical observations
  86. GRB 240928A: SVOM/GRM observation
  87. Fermi GRB 240930A: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  89. GRB 240930A: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 749339671: Global MASTER-Net observations report
  91. GRB 240929A long GRB detected by INTEGRAL
  92. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  93. Fermi GRB 240929A: Global MASTER-Net observations report
  94. GRB 240929A: Fermi GBM Final Real-time Localization
  95. Integral GRB240929.83: Global MASTER-Net observations report
  96. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  97. Konus-Wind detection of GRB 240912A
  98. Swift Trigger 1256950 is probably not a GRB
  99. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  100. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO

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