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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"

19725 results found.

  1. EP240417a: no counterpart detection by SOAR
  2. EP240420a: Xinglong decaying optical counterpart
  3. GRB 240421B: Swift detection of a burst
  4. EP240420a: Nanshan optical counterpart observations
  5. EP240420a: GWAC-F50A optical upper limit
  6. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  7. EP240420a: NOT optical counterpart candidate and potential host
  8. Fermi trigger No 735280430: Global MASTER-Net observations report
  9. GRB240419A: Skynet Optical Afterglow Analysis
  10. GRB240418A - Candidate afterglow from NIRES
  11. GRB 240419B: Swift/UVOT Upper Limits
  12. EP240420a: EP-WXT detection of a fast X-ray transient
  13. GRB 240419A: Swift/UVOT Upper Limits
  14. GRB 240419B: optical afterglow from the NOT
  15. GRB 240419B: Enhanced Swift-XRT position
  16. GRB 240418A: Swift/UVOT Upper Limits
  17. GRB 240419A: REM NIR afterglow detection
  18. GRB 240418A: Swift-XRT refined Analysis
  19. GRB 240419B: Swift detection of a burst
  20. GRB 240411B: Swift/UVOT Detection
  21. GRB 240419A: VLT optical afterglow detection
  22. GRB 240419A: Enhanced Swift-XRT position
  23. EP240416a: J-band observations with WINTER
  24. EP240414a: GMG observation
  25. GRB 240419A: Swift detection of a burst
  26. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  27. GRB 240418A: NOT optical upper limits
  28. GRB 240418A: Enhanced Swift-XRT position
  29. GRB 240418A: AKO Upper Limit
  30. GRB 240418A: Swift detection of a burst
  31. EP240417a: EP-WXT detection of a fast X-ray transient
  32. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  33. GRB 240415A: Glowbug gamma-ray detection
  34. GRB 240414A: Glowbug gamma-ray detection
  35. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  36. EP 240416a: Xinglong and NOT decaying optical counterpart
  37. GRB 240411A: Glowbug gamma-ray detection
  38. EP240416a: Kinder optical counterpart candidate
  39. EP240416a: EP-WXT detection of a fast X-ray transient
  40. GRB 240414A: AbAO optical upprer limit
  41. GRB 240415A: Swift/UVOT Detection
  42. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  43. GRB 240415A: Earliest optical followup with the Kinder observations
  44. GRB 240414A: GMG observation
  45. EP240414a: EP-FXT follow-up observation
  46. GRB 240415A: Enhanced Swift-XRT position
  47. GRB 240415B: Swift ToO observations
  48. GRB 240415A: OHP/T193 optical observations
  49. GRB 240415A: SAO RAS optical observations
  50. GRB 240415A: Mondy optical transient detection
  51. GRB 240414A: Photometric observation from 2.2m CAHA
  52. GRB 240414A: Swift/UVOT Detection
  53. LXT 240402A/GRB 240402B: Swift follow-up observations
  54. GRB 240414A: Mondy optical observations
  55. GRB 240414A: AKO Optical Upper Limit
  56. GRB 240415A: Prompt Swift-XRT observations
  57. EP 240414a: NOT optical counterpart confirmation
  58. GRB240414A : J-band upper limits from WINTER
  59. GRB 240414A: Enhanced Swift-XRT position
  60. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  61. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  62. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  63. EP240413A: GOTO optical upper limits
  64. GRB 240414A: Skynet Optical Afterglow Observations
  65. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  66. IPN triangulation of GRB 240410A
  67. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  68. EP240414a: EP-WXT detection of a fast X-ray transient
  69. IPN triangulation of GRB 240411A
  70. GRB 240414A : MITSuME Akeno optical upper limits
  71. EP240413a: EP-WXT detection of a fast X-ray transient
  72. GRB 240414A : OHP/T193 optical counterpart detection
  73. GRB 240414A: Swift detection of a burst
  74. GRB 240411B: CrAO/ZTSh optical observations
  75. GRB 240411B: Kinder observations with Lulin observatory
  76. GRB 240411B: HiPERCAM/GTC observation
  77. GRB 240411B: 1.3m DFOT Optical observations
  78. GRB 240411B: OHP/T193 optical observations
  79. GRB 240405A: Glowbug gamma-ray detection
  80. GRB 240411B: Enhanced Swift-XRT position
  81. GRB 240411B: LCO optical afterglow detection
  82. GRB 240411B: Swift detection of a burst
  83. EP240408a: EP-WXT detection of a fast X-ray transient
  84. Swift Trigger 1220736: detection of 4U 1543-62.
  85. GRB 240408A: Fermi GBM Final Real-time Localization
  86. Fermi-LAT gamma-ray observations of IceCube-240327B
  87. Fermi-LAT gamma-ray observations of IceCube-240327A
  88. GRB 240402C: Glowbug gamma-ray detection
  89. GRB 240403B: Glowbug gamma-ray detection
  90. GRB 240403A: Glowbug gamma-ray detection
  91. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  92. X-ray transient LXT 240402A: WFST optical upper limits​
  93. GRB/FXT 240402B: Kinder optical counterpart candidate
  94. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  95. X-ray transient LXT 240402A: LEIA detection
  96. X-ray transient EP240331a: Kinder optical upper limits
  97. Transient EP240315a: J-band observations of AT2024eju with WIRC
  98. X-ray transient EP20240331a: MeerLICHT optical upper limits
  99. GRB 240329A: Glowbug gamma-ray detection
  100. GRB 240331A: AstroSat CZTI detection

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