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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"

19722 results found.

  1. GRB 241002A: Enhanced Swift-XRT position
  2. GRB 241002A: Swift detection of a burst
  3. GRB 240930B: Fermi GBM Observation
  4. GRB 241001A: Swift ToO observations
  5. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  6. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  7. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  8. EP240930a: EP-WXT detection of a fast X-ray transient
  9. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  10. AMON NuEM 240926A: Swift XRT Follow-up
  11. GRB 240929A : Leavitt Observatory optical upper limit
  12. GRB 240825A: LBT optical observations
  13. Swift Trigger 1256950 is probably not a GRB
  14. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  15. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  17. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  18. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  19. EP240919a / GRB 240919A: SVOM/VT upper limit
  20. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  21. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  22. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  24. EP240913A/GRB 240913C: AbAO optical upper limit
  25. EP240919a / GRB 240919A: Mondy optical upper limit
  26. EP240913a/GRB 240913C: 1.6m Mephisto observations
  27. EP240918a: SVOM/VT upper limit
  28. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  29. EP240919a / GRB 240919A: REM optical and NIR upper limits
  30. EP240918b and EP240918c: Optical upper limits with Kinder observations
  31. GRB 240414A: further radio observations with the VLA
  32. EP240919a: Optical upper limit with Kinder observations
  33. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  34. GRB 240910A: radio detection with the VLA
  35. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  36. EP240919a: NOT and Gemini optical observations
  37. EP240919a: GOTO optical upper limits
  38. EP240919a: JinShan optical upper limits
  39. EP240919a is likely a GRB event
  40. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  41. GRB 240910A: further Swift observations and confirmation of afterglow
  42. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  43. EP240918a: Swift-XRT observation
  44. EP240918a: JinShan optical upper limits
  45. EP240918a: Optical upper limits with Kinder observations
  46. EP240918a: GMG Optical Upper Limit
  47. EP240918a: an X-ray transient detected by Einstein Probe
  48. IPN triangulation of GRB 240913C / EP 240913a
  49. GRB 240821A: radio observation with the VLA
  50. GRB 240916A: Swift-XRT afterglow detection
  51. GRB 240916A: Swift ToO observations
  52. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  53. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  54. EP240913a: VLT/HAWK-I near-infrared upper limits
  55. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  56. GRB 240914A: Swift-XRT observations
  57. GRB 240914B: AstroSat CZTI detection
  58. GRB 240910A: SVOM/VT optical observations
  59. GRB 240914A: Swift ToO observations
  60. EP240913a: NOT optical upper limits
  61. EP240913a: JinShan optical upper limits
  62. EP240913a: ESO-NTT optical observations
  63. GRB 240914A: ESO-NTT optical observations
  64. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  65. GRB 240905E: further NOT optical observations
  66. EP240913a: EP-WXT detection of a fast X-ray transient
  67. GRB 240911A: LCO optical observations
  68. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  69. GRB 240912A: Swift/UVOT Detection
  70. GRB 240912A: J-band observations with WINTER
  71. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  72. GRB 240911A: Tiled Swift observations
  73. GRB 240912A: Enhanced Swift-XRT position
  74. GRB 240912A: Redshift from OSIRIS+/GTC
  75. Fast X-ray Transient EP240801a: GMRT radio observations
  76. GRB 240912A: Swift detection of a burst with an optical counterpart
  77. GRB 240910A: JinShan optical observations
  78. GRB 240910A: Swift ToO observations
  79. GRB 240825A: 7DT Optical Upper Limit
  80. GRB 240905E: SVOM/VT optical observations
  81. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  82. GRB 240910A: SVOM/GRM observation
  83. EP240908a: Mondy and AbAO follow-up observations
  84. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  85. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  86. EP240908a: TRT optical upper limit
  87. EP240908a: EP detection of a fast X-ray transient
  88. GRB 240908A: Fermi GBM Final Real-time Localization
  89. GRB 240905E: GIT optical upper limit
  90. GRB 240905E: Gaoyazi/GOT optical upper limits
  91. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  92. GRB 240905B: Swift ToO observations
  93. GRB 240905E: J-band observations with WINTER
  94. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  95. GRB 240905E: AKO Optical Upper Limit
  96. GRB 240905E: SVOM/C-GFT optical upper limit
  97. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  98. GRB 240905E: NOT optical upper limits
  99. GRB 240905E: REM optical/NIR upper limits
  100. GRB 240905E: LCOGT Optical Upper Limit

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