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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"

28231 results found.

  1. GRB 240421A: Glowbug gamma-ray detection
  2. GRB 240414A: radio detection with the VLA
  3. Fermi-LAT gamma-ray observations of IceCube-240419A
  4. GRB 240414A: AMI-LA radio observations
  5. GRB 240414A: LBT optical detection
  6. GRB 240419B : MITSuME Akeno optical upper limits
  7. GRB 240415B: Swift-XRT observations
  8. GRB 240415A: Swift-XRT refined Analysis
  9. GRB240421B: Zadko Observations
  10. GRB 240421B: Fermi GBM Observation
  11. GRB 240421B: Swift-XRT refined Analysis
  12. GRB240421B: BOOTES-5/JGT optical upper limit
  13. GRB 240421B: J-band upper limits from WINTER
  14. GRB 240421B: Swift/UVOT Upper Limits
  15. GRB 240421B: Enhanced Swift-XRT position
  16. EP240417a: no counterpart detection by SOAR
  17. EP240420a: Xinglong decaying optical counterpart
  18. GRB 240421B: Swift detection of a burst
  19. EP240420a: Nanshan optical counterpart observations
  20. EP240420a: GWAC-F50A optical upper limit
  21. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  22. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  23. EP240420a: NOT optical counterpart candidate and potential host
  24. GRB240419A: Skynet Optical Afterglow Analysis
  25. GRB240418A - Candidate afterglow from NIRES
  26. GRB 240419B: Swift/UVOT Upper Limits
  27. EP240420a: EP-WXT detection of a fast X-ray transient
  28. GRB 240419A: Swift/UVOT Upper Limits
  29. GRB 240419B: Swift-XRT refined Analysis
  30. GRB 240419B: optical afterglow from the NOT
  31. EP240414a: Near-IR observations with NIRES and WINTER
  32. GRB 240419B: Enhanced Swift-XRT position
  33. GRB 240418A: Swift/UVOT Upper Limits
  34. GRB 240419A: REM NIR afterglow detection
  35. GRB 240419A: Swift-XRT refined Analysis
  36. GRB 240418A: Swift-XRT refined Analysis
  37. GRB 240419B: Swift detection of a burst
  38. GRB 240411B: Swift/UVOT Detection
  39. GRB 240419A: VLT optical afterglow detection
  40. GRB 240419A: Enhanced Swift-XRT position
  41. EP240416a: J-band observations with WINTER
  42. EP240414a: GMG observation
  43. GRB 240419A: Swift detection of a burst
  44. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  45. GRB 240418A: NOT optical upper limits
  46. GRB 240418A: Enhanced Swift-XRT position
  47. GRB 240418A: AKO Upper Limit
  48. GRB 240418A: Swift detection of a burst
  49. EP240417a: EP-WXT detection of a fast X-ray transient
  50. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  51. Improved IPN triangulation of GRB 240411A
  52. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  53. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  54. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 240415A: Glowbug gamma-ray detection
  56. GRB 240414A: Glowbug gamma-ray detection
  57. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  58. GRB 240415B: GECAM-B detection
  59. EP 240416a: Xinglong and NOT decaying optical counterpart
  60. GRB 240415A: Swift-BAT refined analysis
  61. GRB 240411A: Glowbug gamma-ray detection
  62. GRB 240414A: Swift-BAT refined analysis
  63. EP240416a: Kinder optical counterpart candidate
  64. EP240416a: EP-WXT detection of a fast X-ray transient
  65. GRB 240414A: AbAO optical upprer limit
  66. GRB 240415A: Swift/UVOT Detection
  67. GRB 240415A: Fermi GBM Observation
  68. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  69. GRB 240415A: Earliest optical followup with the Kinder observations
  70. GRB 240414A: GMG observation
  71. EP240414a: EP-FXT follow-up observation
  72. GRB 240415A: Enhanced Swift-XRT position
  73. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  74. GRB 240415A: OHP/T193 optical observations
  75. GRB 240415A: SAO RAS optical observations
  76. GRB 240414A: Fermi GBM Observation
  77. GRB 240415A: Mondy optical transient detection
  78. GRB 240414A: Photometric observation from 2.2m CAHA
  79. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 240414A: Swift/UVOT Detection
  81. LXT 240402A/GRB 240402B: Swift follow-up observations
  82. GRB 240414A: Mondy optical observations
  83. GRB 240414A: AKO Optical Upper Limit
  84. X-ray transient EP 240414a - GTC spectroscopic observations
  85. GRB 240415A: Prompt Swift-XRT observations
  86. GRB 240415A: Swift detection of a burst
  87. EP240413a: Upper limits from GECAM-B Observation
  88. EP 240414a: NOT optical counterpart confirmation
  89. GRB 240414A: Swift-XRT refined Analysis
  90. GRB240414A : J-band upper limits from WINTER
  91. GRB 240414A: Enhanced Swift-XRT position
  92. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  93. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  94. EP240413A: GOTO optical upper limits
  95. GRB 240414A: Skynet Optical Afterglow Observations
  96. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  97. IPN triangulation of GRB 240410A
  98. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  99. EP240414a: EP-WXT detection of a fast X-ray transient
  100. IPN triangulation of GRB 240411A

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