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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"

21947 results found.

  1. IceCube-241006A: No candidates from the Zwicky Transient Facility
  2. GRB 241006A: GRANDMA optical upper limits
  3. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  4. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  5. GRB 240910A: LBT optical observations
  6. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  7. GRB 241006A: PRIME near-infrared upper limits
  8. GRB 241006A: Swift/UVOT Upper Limits
  9. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  10. GRB 241001A: Swift-XRT afterglow detection
  11. GRB 241006A: Enhanced Swift-XRT position
  12. GRB 241006A: Swift detection of a burst
  13. GRB 240930B: SVOM/C-GFT optical upper limit
  14. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  15. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  16. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  17. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  18. GRB 241002C: SVOM/C-GFT optical upper limit
  19. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  20. Konus-Wind detection of GRB 240926A
  21. GRB 241002B: PRIME near-infrared detection
  22. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  23. IPN triangulation of GRB 240930B / EP 240930a
  24. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  25. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  26. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  27. GRB 241002C : MITSuME Akeno optical upper limits
  28. GRB241001A: REM optical/NIR upper limits
  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 241002B: GOTO optical counterpart candidate
  35. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  36. GRB 240929A: Liverpool Telescope prompt followup observations
  37. GRB 241001A: Swift-XRT observations
  38. GRB241001A: optical afterglow candidate
  39. GRB 241002A: Enhanced Swift-XRT position
  40. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  41. GRB 241002A: Swift detection of a burst
  42. GRB 240930B: Fermi GBM Observation
  43. GRB 240930B: GRBAlpha detection
  44. GRB 240929A: GRBAlpha detection
  45. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  46. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  47. EP240930a: GOTO optical upper limits
  48. EP240930a: EP-WXT detection of a fast X-ray transient
  49. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  50. GRB 240929A : Leavitt Observatory optical upper limit
  51. GRB 240825A: LBT optical observations
  52. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  53. GRB 240929A long GRB detected by INTEGRAL
  54. Konus-Wind detection of GRB 240912A
  55. Swift Trigger 1256950 is probably not a GRB
  56. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  59. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  60. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  61. Konus-Wind detection of GRB 240905B
  62. EP240919a / GRB 240919A: SVOM/VT upper limit
  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. GRB 240905B: VZLUSAT-2 detection
  68. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  70. GRB 240918B: AstroSat CZTI detection
  71. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  73. EP240913A/GRB 240913C: AbAO optical upper limit
  74. EP240919a / GRB 240919A: Mondy optical upper limit
  75. EP240913a/GRB 240913C: 1.6m Mephisto observations
  76. EP240918a: SVOM/VT upper limit
  77. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  78. EP240919a / GRB 240919A: REM optical and NIR upper limits
  79. EP240918b and EP240918c: Optical upper limits with Kinder observations
  80. GRB 240414A: further radio observations with the VLA
  81. EP240919a: Optical upper limit with Kinder observations
  82. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  83. GRB 240910A: radio detection with the VLA
  84. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  85. EP240919a: NOT and Gemini optical observations
  86. EP240919a: GOTO optical upper limits
  87. EP240919a: JinShan optical upper limits
  88. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  89. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  90. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  91. GRB 240910A: further Swift observations and confirmation of afterglow
  92. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  93. EP240918a: JinShan optical upper limits
  94. EP240918a: YAHPT Optical Upper Limit
  95. EP240918a: Optical upper limits with Kinder observations
  96. EP240918a: GMG Optical Upper Limit
  97. GRB 240916A: GRBAlpha detection
  98. GRB 240914B: GRBAlpha detection
  99. EP240918a: an X-ray transient detected by Einstein Probe
  100. IPN triangulation of GRB 240913C / EP 240913a

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