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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

19124 results found.

  1. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  2. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  3. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  4. GRB 241002C : MITSuME Akeno optical upper limits
  5. GRB241001A: REM optical/NIR upper limits
  6. GRB 241002A: Swift/UVOT Upper Limits
  7. EP240930a: Liverpool Telescope observations
  8. GRB 241002A: LCOGT Optical Upper Limits
  9. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  10. GRB 241001A: Swift/UVOT Detection
  11. GRB 241002B: GOTO optical counterpart candidate
  12. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  13. GRB 240929A: Liverpool Telescope prompt followup observations
  14. GRB 241001A: Swift-XRT observations
  15. GRB241001A: optical afterglow candidate
  16. GRB 241002A: Enhanced Swift-XRT position
  17. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  18. GRB 241002A: Swift detection of a burst
  19. GRB 240930B: Fermi GBM Observation
  20. GRB 240930B: GRBAlpha detection
  21. GRB 240929A: GRBAlpha detection
  22. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  23. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  24. EP240930a: GOTO optical upper limits
  25. EP240930a: EP-WXT detection of a fast X-ray transient
  26. LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
  27. GRB 240929A : Leavitt Observatory optical upper limit
  28. GRB 240825A: LBT optical observations
  29. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  30. GRB 240929A long GRB detected by INTEGRAL
  31. Konus-Wind detection of GRB 240912A
  32. Swift Trigger 1256950 is probably not a GRB
  33. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  35. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  36. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  37. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  38. Konus-Wind detection of GRB 240905B
  39. EP240919a / GRB 240919A: SVOM/VT upper limit
  40. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  41. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  42. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  43. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  44. GRB 240905B: VZLUSAT-2 detection
  45. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  47. GRB 240918B: AstroSat CZTI detection
  48. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  50. EP240913A/GRB 240913C: AbAO optical upper limit
  51. EP240919a / GRB 240919A: Mondy optical upper limit
  52. EP240913a/GRB 240913C: 1.6m Mephisto observations
  53. EP240918a: SVOM/VT upper limit
  54. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  55. EP240919a / GRB 240919A: REM optical and NIR upper limits
  56. EP240918b and EP240918c: Optical upper limits with Kinder observations
  57. GRB 240414A: further radio observations with the VLA
  58. EP240919a: Optical upper limit with Kinder observations
  59. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  60. GRB 240910A: radio detection with the VLA
  61. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  62. EP240919a: NOT and Gemini optical observations
  63. EP240919a: GOTO optical upper limits
  64. EP240919a: JinShan optical upper limits
  65. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  67. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  68. GRB 240910A: further Swift observations and confirmation of afterglow
  69. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  70. EP240918a: JinShan optical upper limits
  71. EP240918a: YAHPT Optical Upper Limit
  72. EP240918a: Optical upper limits with Kinder observations
  73. EP240918a: GMG Optical Upper Limit
  74. GRB 240916A: GRBAlpha detection
  75. GRB 240914B: GRBAlpha detection
  76. EP240918a: an X-ray transient detected by Einstein Probe
  77. IPN triangulation of GRB 240913C / EP 240913a
  78. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  79. GRB 240821A: radio observation with the VLA
  80. GRB 240916A: Swift-XRT afterglow detection
  81. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  82. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  83. EP240913a: VLT/HAWK-I near-infrared upper limits
  84. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  86. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  87. GRB 240914A: Swift-XRT observations
  88. GRB 240914B: AstroSat CZTI detection
  89. EP240913A / GRB 240913C: AstroSat CZTI detection
  90. GRB 240910A: SVOM/VT optical observations
  91. EP240913a: NOT optical upper limits
  92. EP240913a: JinShan optical upper limits
  93. EP240913a: ESO-NTT optical observations
  94. GRB 240914A: ESO-NTT optical observations
  95. GRB 240905E: further NOT optical observations
  96. EP240913a: A GRB Event
  97. EP240913a: EP-WXT detection of a fast X-ray transient
  98. GRB 240911A: LCO optical observations
  99. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  100. GRB 240912A: Swift/UVOT Detection

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