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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"
  1. Fermi GRB 241013B: Global MASTER-Net observations report
  2. Integral GRB241013.04: Global MASTER-Net observations report
  3. GRB 241013B: Fermi GBM Final Real-time Localization
  4. GRB 241013A: a long GRB detected by INTEGRAL
  5. GRB 241013A: Fermi GBM Final Real-time Localization
  6. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  7. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  8. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  9. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  10. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  11. GRB 241011A: Fermi GBM Final Real-time Localization
  12. GRB 241009A: GRANDMA optical upper limits
  13. GRB 241009A: Swift-XRT afterglow detection
  14. GRB 241010A: JinShan optical observations and potential host galaxy
  15. GRB 241006A: ATCA Radio Upper Limits
  16. GRB 241010A: Swift-XRT refined Analysis
  17. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  18. Fermi trigger No 750211959: Global MASTER-Net observations report
  19. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  20. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  21. Swift GRB 241010A: Global MASTER-Net observations report
  22. Fermi trigger No 750291012: Global MASTER-Net observations report
  23. GRB 241010A: J-band observations with WINTER
  24. LIGO/Virgo/KAGRA S241009an: Updated Sky localization
  25. Fermi GRB 241010B: Global MASTER-Net observations report
  26. GRB 241010B: Fermi GBM Final Real-time Localization
  27. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 241010A: Enhanced Swift-XRT position
  29. GRB 241010A: LCO optical observations
  30. GRB 241010A: Swift detection of a burst with an optical counterpart
  31. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  32. GRB 241006A: Swift-BAT refined analysis
  33. GRB 241009A: Swift ToO observations
  34. LIGO/Virgo/KAGRA S241009l: Updated Sky localization
  35. LIGO/Virgo/KAGRA S241009em: Identification of a GW compact binary merger candidate
  36. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  37. GRB 241008A: Fermi GBM Observation
  38. GRB 241008A: Fermi-LAT detection
  39. GRB 241002B: Swift-XRT afterglow detection
  40. LIGO/Virgo/KAGRA S241009an: Identification of a GW compact binary merger candidate
  41. GRB 241002A: NOT optical upper limits
  42. LIGO/Virgo/KAGRA S241009l: Identification of a GW compact binary merger candidate
  43. Fermi GRB 241008A: Global MASTER-Net observations report
  44. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  45. GRB 241008A: Fermi GBM Final Real-time Localization
  46. IceCube-241006A: No candidates from the Zwicky Transient Facility
  47. GRB 241006A: GRANDMA optical upper limits
  48. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  49. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  50. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  51. GRB 240910A: LBT optical observations
  52. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  53. GRB 241006A: Swift-XRT refined Analysis
  54. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  55. GRB 241006A: PRIME near-infrared upper limits
  56. GRB 241006A: Swift/UVOT Upper Limits
  57. GRB 241006A: SVOM/VT follow-up and optical upper limit
  58. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  59. IceCube Alert 241006.94: Global MASTER-Net observations report
  60. GRB 241001A: Swift-XRT afterglow detection
  61. GRB 241006A: Enhanced Swift-XRT position
  62. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 241006A: Swift detection of a burst
  64. Swift GRB241006.91: Global MASTER-Net observations report
  65. GRB 240930B: SVOM/C-GFT optical upper limit
  66. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S241005bo: Retraction of GW compact binary merger candidate
  68. Fermi trigger No 749721670: Global MASTER-Net observations report
  69. GRB 241004A: SVOM/GRM observation
  70. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  71. GRB 240930B / EP 240930a: SVOM/GRM observation
  72. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  73. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  74. GRB 241002B: Fermi GBM Observation
  75. Fermi trigger No 749735279: Global MASTER-Net observations report
  76. Fermi trigger No 749630753: Global MASTER-Net observations report
  77. Fermi trigger No 749693019: Global MASTER-Net observations report
  78. GRB 241002B: Swift-XRT observations
  79. GRB 241002C: SVOM/C-GFT optical upper limit
  80. GRB 241002A: Swift-BAT refined analysis
  81. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 241002B: Swift ToO observations
  83. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  84. Konus-Wind detection of GRB 240926A
  85. GRB 241002B: PRIME near-infrared detection
  86. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  87. GRB 241002C: Swift ToO observations
  88. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  89. IPN triangulation of GRB 240930B / EP 240930a
  90. GRB 241001A : SVOM/VT optical detection
  91. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  92. GRB 241002D: SVOM/GRM observation
  93. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  94. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  95. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  96. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  97. GRB 241002C : MITSuME Akeno optical upper limits
  98. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  99. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  100. GRB241001A: REM optical/NIR upper limits

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