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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"

32551 results found.

  1. Konus-Wind detection of GRB 240926A
  2. GRB 241002B: PRIME near-infrared detection
  3. GRB 241002C: Swift ToO observations
  4. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  5. IPN triangulation of GRB 240930B / EP 240930a
  6. GRB 241001A : SVOM/VT optical detection
  7. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  8. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  9. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  10. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  11. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  12. GRB 241002C : MITSuME Akeno optical upper limits
  13. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  14. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  15. GRB241001A: REM optical/NIR upper limits
  16. LIGO/Virgo/KAGRA S241002e: Updated Sky localization
  17. GRB 241002A: Swift/UVOT Upper Limits
  18. EP240930a: Liverpool Telescope observations
  19. GRB 241002A: LCOGT Optical Upper Limits
  20. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  21. GRB 241001A: Swift/UVOT Detection
  22. GRB 241001A: VLT/X-shooter redshift
  23. GRB 241002B: GOTO optical counterpart candidate
  24. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  25. GRB 241001A: correction to GCN 37667
  26. GRB 240929A: Liverpool Telescope prompt followup observations
  27. Fermi GRB 241002B: Global MASTER-Net observations report
  28. GRB 241001A: Swift-XRT observations
  29. GRB241001A: optical afterglow candidate
  30. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  31. LIGO/Virgo/KAGRA S240930du: Updated Sky localization
  32. GRB 240930B: Fermi GBM Observation
  33. GRB 241001A: Swift ToO observations
  34. GRB 240930B: GRBAlpha detection
  35. GRB 240929A: GRBAlpha detection
  36. EP240930a : KAIT optical upper limit
  37. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  38. EP240930a: EP-FXT follow-up observation update
  39. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  40. EP240930a: GOTO optical upper limits
  41. GRB 240929A: SVOM/GRM observation
  42. EP EP240930a: Global MASTER-Net observations report
  43. EP240930a: EP-WXT detection of a fast X-ray transient
  44. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  45. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  46. AMON NuEM 240926A: Swift XRT Follow-up
  47. GRB 240929A : Leavitt Observatory optical upper limit
  48. Fermi GRB 240930B: Global MASTER-Net observations report
  49. IPN triangulation of GRB 240926A
  50. GRB 240825A: LBT optical observations
  51. Fermi GRB 240930A: Global MASTER-Net observations report
  52. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  53. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  54. GRB 240929A long GRB detected by INTEGRAL
  55. Fermi GRB 240929A: Global MASTER-Net observations report
  56. Konus-Wind detection of GRB 240912A
  57. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  58. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  59. Konus-Wind detection of GRB 240905B
  60. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  61. EP240919a / GRB 240919A: SVOM/VT upper limit
  62. EP240918b and EP240918c: EP-FXT follow-up observations
  63. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  64. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  65. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  66. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  67. Konus-Wind detection of GRB 240918B
  68. IPN triangulation of GRB 240918B
  69. GRB 240905B: VZLUSAT-2 detection
  70. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  71. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  72. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  73. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  74. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  75. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  76. EP trigger ID 01709059262: correction to the observation start time and source localization
  77. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo S240919bn: GOTO optical upper limits
  80. GRB 240918B: AstroSat CZTI detection
  81. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  83. EP240919a: EP-FXT follow-up observation update
  84. EP240913A/GRB 240913C: AbAO optical upper limit
  85. EP240919a / GRB 240919A: Mondy optical upper limit
  86. EP240913a/GRB 240913C: 1.6m Mephisto observations
  87. EP240918a: SVOM/VT upper limit
  88. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  89. EP240919a / GRB 240919A: REM optical and NIR upper limits
  90. EP240919a / GRB 240919A: KAIT optical upper limit
  91. EP240918b and EP240918c: Optical upper limits with Kinder observations
  92. GRB 240414A: further radio observations with the VLA
  93. EP240919a: Optical upper limit with Kinder observations
  94. GRB 240919A / EP240919a: SVOM/GRM observation
  95. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  96. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  97. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  98. EP EP240919a: Global MASTER-Net observations report
  99. GRB 240910A: radio detection with the VLA
  100. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit

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