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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"

19715 results found.

  1. EP240930a: EP-WXT detection of a fast X-ray transient
  2. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  3. AMON NuEM 240926A: Swift XRT Follow-up
  4. GRB 240929A : Leavitt Observatory optical upper limit
  5. GRB 240825A: LBT optical observations
  6. Swift Trigger 1256950 is probably not a GRB
  7. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  8. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  9. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  10. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  11. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  12. EP240919a / GRB 240919A: SVOM/VT upper limit
  13. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  14. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  17. EP240913A/GRB 240913C: AbAO optical upper limit
  18. EP240919a / GRB 240919A: Mondy optical upper limit
  19. EP240913a/GRB 240913C: 1.6m Mephisto observations
  20. EP240918a: SVOM/VT upper limit
  21. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  22. EP240919a / GRB 240919A: REM optical and NIR upper limits
  23. EP240918b and EP240918c: Optical upper limits with Kinder observations
  24. GRB 240414A: further radio observations with the VLA
  25. EP240919a: Optical upper limit with Kinder observations
  26. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  27. GRB 240910A: radio detection with the VLA
  28. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  29. EP240919a: NOT and Gemini optical observations
  30. EP240919a: GOTO optical upper limits
  31. EP240919a: JinShan optical upper limits
  32. EP240919a is likely a GRB event
  33. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  34. GRB 240910A: further Swift observations and confirmation of afterglow
  35. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  36. EP240918a: Swift-XRT observation
  37. EP240918a: JinShan optical upper limits
  38. EP240918a: Optical upper limits with Kinder observations
  39. EP240918a: GMG Optical Upper Limit
  40. EP240918a: an X-ray transient detected by Einstein Probe
  41. IPN triangulation of GRB 240913C / EP 240913a
  42. GRB 240821A: radio observation with the VLA
  43. GRB 240916A: Swift-XRT afterglow detection
  44. GRB 240916A: Swift ToO observations
  45. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  46. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  47. EP240913a: VLT/HAWK-I near-infrared upper limits
  48. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  49. GRB 240914A: Swift-XRT observations
  50. GRB 240914B: AstroSat CZTI detection
  51. GRB 240910A: SVOM/VT optical observations
  52. GRB 240914A: Swift ToO observations
  53. EP240913a: NOT optical upper limits
  54. EP240913a: JinShan optical upper limits
  55. EP240913a: ESO-NTT optical observations
  56. GRB 240914A: ESO-NTT optical observations
  57. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  58. GRB 240905E: further NOT optical observations
  59. EP240913a: EP-WXT detection of a fast X-ray transient
  60. GRB 240911A: LCO optical observations
  61. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  62. GRB 240912A: Swift/UVOT Detection
  63. GRB 240912A: J-band observations with WINTER
  64. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  65. GRB 240911A: Tiled Swift observations
  66. GRB 240912A: Enhanced Swift-XRT position
  67. GRB 240912A: Redshift from OSIRIS+/GTC
  68. Fast X-ray Transient EP240801a: GMRT radio observations
  69. GRB 240912A: Swift detection of a burst with an optical counterpart
  70. GRB 240910A: JinShan optical observations
  71. GRB 240910A: Swift ToO observations
  72. GRB 240825A: 7DT Optical Upper Limit
  73. GRB 240905E: SVOM/VT optical observations
  74. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  75. GRB 240910A: SVOM/GRM observation
  76. EP240908a: Mondy and AbAO follow-up observations
  77. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  79. EP240908a: TRT optical upper limit
  80. EP240908a: EP detection of a fast X-ray transient
  81. GRB 240908A: Fermi GBM Final Real-time Localization
  82. GRB 240905E: GIT optical upper limit
  83. GRB 240905E: Gaoyazi/GOT optical upper limits
  84. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  85. GRB 240905B: Swift ToO observations
  86. GRB 240905E: J-band observations with WINTER
  87. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  88. GRB 240905E: AKO Optical Upper Limit
  89. GRB 240905E: SVOM/C-GFT optical upper limit
  90. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  91. GRB 240905E: NOT optical upper limits
  92. GRB 240905E: REM optical/NIR upper limits
  93. GRB 240905E: LCOGT Optical Upper Limit
  94. GRB 240905E: Swift/UVOT Upper Limits
  95. GRB 240905E: SAO RAS optical upper limit
  96. GRB 240905E: Nanshan/HMT optical upper limit
  97. GRB 240905E: Swift detection of a burst
  98. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  99. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  100. GRB 240825A: MeerLICHT afterglow detection

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