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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"

28235 results found.

  1. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo/KAGRA S240422ed: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
  5. GRB 240421A: Glowbug gamma-ray detection
  6. GRB 240414A: radio detection with the VLA
  7. Fermi-LAT gamma-ray observations of IceCube-240419A
  8. GRB 240414A: AMI-LA radio observations
  9. GRB 240414A: LBT optical detection
  10. GRB 240419B : MITSuME Akeno optical upper limits
  11. GRB 240415B: Swift-XRT observations
  12. GRB 240415A: Swift-XRT refined Analysis
  13. GRB240421B: Zadko Observations
  14. GRB 240421B: Fermi GBM Observation
  15. GRB 240421B: Swift-XRT refined Analysis
  16. GRB240421B: BOOTES-5/JGT optical upper limit
  17. GRB 240421B: J-band upper limits from WINTER
  18. GRB 240421B: Swift/UVOT Upper Limits
  19. GRB 240421B: Enhanced Swift-XRT position
  20. EP240417a: no counterpart detection by SOAR
  21. EP240420a: Xinglong decaying optical counterpart
  22. GRB 240421B: Swift detection of a burst
  23. EP240420a: Nanshan optical counterpart observations
  24. EP240420a: GWAC-F50A optical upper limit
  25. LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
  26. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  27. EP240420a: NOT optical counterpart candidate and potential host
  28. GRB240419A: Skynet Optical Afterglow Analysis
  29. GRB240418A - Candidate afterglow from NIRES
  30. GRB 240419B: Swift/UVOT Upper Limits
  31. EP240420a: EP-WXT detection of a fast X-ray transient
  32. GRB 240419A: Swift/UVOT Upper Limits
  33. GRB 240419B: Swift-XRT refined Analysis
  34. GRB 240419B: optical afterglow from the NOT
  35. EP240414a: Near-IR observations with NIRES and WINTER
  36. GRB 240419B: Enhanced Swift-XRT position
  37. GRB 240418A: Swift/UVOT Upper Limits
  38. GRB 240419A: REM NIR afterglow detection
  39. GRB 240419A: Swift-XRT refined Analysis
  40. GRB 240418A: Swift-XRT refined Analysis
  41. GRB 240419B: Swift detection of a burst
  42. GRB 240411B: Swift/UVOT Detection
  43. GRB 240419A: VLT optical afterglow detection
  44. GRB 240419A: Enhanced Swift-XRT position
  45. EP240416a: J-band observations with WINTER
  46. EP240414a: GMG observation
  47. GRB 240419A: Swift detection of a burst
  48. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  49. GRB 240418A: NOT optical upper limits
  50. GRB 240418A: Enhanced Swift-XRT position
  51. GRB 240418A: AKO Upper Limit
  52. GRB 240418A: Swift detection of a burst
  53. EP240417a: EP-WXT detection of a fast X-ray transient
  54. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  55. Improved IPN triangulation of GRB 240411A
  56. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  57. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  58. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 240415A: Glowbug gamma-ray detection
  60. GRB 240414A: Glowbug gamma-ray detection
  61. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  62. GRB 240415B: GECAM-B detection
  63. EP 240416a: Xinglong and NOT decaying optical counterpart
  64. GRB 240415A: Swift-BAT refined analysis
  65. GRB 240411A: Glowbug gamma-ray detection
  66. GRB 240414A: Swift-BAT refined analysis
  67. EP240416a: Kinder optical counterpart candidate
  68. EP240416a: EP-WXT detection of a fast X-ray transient
  69. GRB 240414A: AbAO optical upprer limit
  70. GRB 240415A: Swift/UVOT Detection
  71. GRB 240415A: Fermi GBM Observation
  72. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  73. GRB 240415A: Earliest optical followup with the Kinder observations
  74. GRB 240414A: GMG observation
  75. EP240414a: EP-FXT follow-up observation
  76. GRB 240415A: Enhanced Swift-XRT position
  77. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  78. GRB 240415A: OHP/T193 optical observations
  79. GRB 240415A: SAO RAS optical observations
  80. GRB 240414A: Fermi GBM Observation
  81. GRB 240415A: Mondy optical transient detection
  82. GRB 240414A: Photometric observation from 2.2m CAHA
  83. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 240414A: Swift/UVOT Detection
  85. LXT 240402A/GRB 240402B: Swift follow-up observations
  86. GRB 240414A: Mondy optical observations
  87. GRB 240414A: AKO Optical Upper Limit
  88. X-ray transient EP 240414a - GTC spectroscopic observations
  89. GRB 240415A: Prompt Swift-XRT observations
  90. GRB 240415A: Swift detection of a burst
  91. EP240413a: Upper limits from GECAM-B Observation
  92. EP 240414a: NOT optical counterpart confirmation
  93. GRB 240414A: Swift-XRT refined Analysis
  94. GRB240414A : J-band upper limits from WINTER
  95. GRB 240414A: Enhanced Swift-XRT position
  96. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  97. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  98. EP240413A: GOTO optical upper limits
  99. GRB 240414A: Skynet Optical Afterglow Observations
  100. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3

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