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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"

32763 results found.

  1. GRB 240930B: SVOM/C-GFT optical upper limit
  2. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  3. GRB 240930B / EP 240930a: SVOM/GRM observation
  4. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  5. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  6. GRB 241002B: Fermi GBM Observation
  7. GRB 241002B: Swift-XRT observations
  8. GRB 241002C: SVOM/C-GFT optical upper limit
  9. GRB 241002A: Swift-BAT refined analysis
  10. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  11. GRB 241002B: Swift ToO observations
  12. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  13. Konus-Wind detection of GRB 240926A
  14. GRB 241002B: PRIME near-infrared detection
  15. GRB 241002C: Swift ToO observations
  16. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  17. IPN triangulation of GRB 240930B / EP 240930a
  18. GRB 241001A : SVOM/VT optical detection
  19. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  20. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  21. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  22. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  23. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  24. GRB 241002C : MITSuME Akeno optical upper limits
  25. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  26. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  27. GRB241001A: REM optical/NIR upper limits
  28. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  29. GRB 241002A: Swift/UVOT Upper Limits
  30. EP240930a: Liverpool Telescope observations
  31. GRB 241002A: LCOGT Optical Upper Limits
  32. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  33. GRB 241001A: Swift/UVOT Detection
  34. GRB 241001A: VLT/X-shooter redshift
  35. GRB 241002B: GOTO optical counterpart candidate
  36. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  37. GRB 241001A: correction to GCN 37667
  38. GRB 240929A: Liverpool Telescope prompt followup observations
  39. Fermi GRB 241002B: Global MASTER-Net observations report
  40. GRB 241001A: Swift-XRT observations
  41. GRB241001A: optical afterglow candidate
  42. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  44. GRB 240930B: Fermi GBM Observation
  45. GRB 241001A: Swift ToO observations
  46. GRB 240930B: GRBAlpha detection
  47. GRB 240929A: GRBAlpha detection
  48. EP240930a : KAIT optical upper limit
  49. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  50. EP240930a: EP-FXT follow-up observation update
  51. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  52. EP240930a: GOTO optical upper limits
  53. GRB 240929A: SVOM/GRM observation
  54. EP EP240930a: Global MASTER-Net observations report
  55. EP240930a: EP-WXT detection of a fast X-ray transient
  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. AMON NuEM 240926A: Swift XRT Follow-up
  59. GRB 240929A : Leavitt Observatory optical upper limit
  60. Fermi GRB 240930B: Global MASTER-Net observations report
  61. IPN triangulation of GRB 240926A
  62. GRB 240825A: LBT optical observations
  63. Fermi GRB 240930A: Global MASTER-Net observations report
  64. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  65. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  66. GRB 240929A long GRB detected by INTEGRAL
  67. Fermi GRB 240929A: Global MASTER-Net observations report
  68. Konus-Wind detection of GRB 240912A
  69. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  70. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  71. Konus-Wind detection of GRB 240905B
  72. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  73. EP240919a / GRB 240919A: SVOM/VT upper limit
  74. EP240918b and EP240918c: EP-FXT follow-up observations
  75. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  76. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  77. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  78. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  79. Konus-Wind detection of GRB 240918B
  80. IPN triangulation of GRB 240918B
  81. GRB 240905B: VZLUSAT-2 detection
  82. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  83. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  84. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  85. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  86. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  87. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  88. EP trigger ID 01709059262: correction to the observation start time and source localization
  89. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo S240919bn: GOTO optical upper limits
  92. GRB 240918B: AstroSat CZTI detection
  93. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  95. EP240919a: EP-FXT follow-up observation update
  96. EP240913A/GRB 240913C: AbAO optical upper limit
  97. EP240919a / GRB 240919A: Mondy optical upper limit
  98. EP240913a/GRB 240913C: 1.6m Mephisto observations
  99. EP240918a: SVOM/VT upper limit
  100. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a

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