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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

26364 results found.

  1. GRB 240802A: SVOM/GRM observation
  2. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  3. Fermi trigger No 744278264: Global MASTER-Net observations report
  4. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  5. GRB 240802A: AstroSat CZTI detection of a long burst
  6. EP240801a: further SAO RAS optical observations
  7. EP240801a: optical observations at CrAO and AbAO
  8. EP240801a: Leavitt Observatory optical observations
  9. EP240801a: SAO RAS optical observations
  10. EP240801a: JinShan optical observations
  11. GRB 240727C: SVOM/GRM observation
  12. EP240801a: follow-up observation with LCOGT
  13. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  14. GRB 240730A: Swift-BAT refined analysis
  15. EP240801a: GSP follow-up observations of the candidate counterpart
  16. EP240801a: Kinder follow-up observations of the candidate counterpart
  17. EP240801a: GMG observation
  18. EP240801a: TRT optical counterpart detection
  19. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  20. GRB 240801B: AstroSat CZTI detection of a bright long burst
  21. GRB 240801A: Fermi GBM Final Real-time Localization
  22. GRB 240730C: AstroSat CZTI detection of a long burst
  23. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  24. GRB240730A: BOOTES-5/JGT early optical upper limit
  25. Swift GRB 240730A: Global MASTER-Net observations report
  26. GRB 240730A: Swift-XRT refined Analysis
  27. GRB 240715A: Swift-XRT afterglow detection
  28. GRB 240730A: Swift/UVOT Upper Limits
  29. GRB 240730A: Enhanced Swift-XRT position
  30. GRB 240730A: Swift detection of a burst
  31. GRB 240727A: Swift-BAT refined analysis
  32. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  33. GRB 240727A: observations of optical counterpart.
  34. GRB 240727B: Swift-XRT observations
  35. Fermi GRB 240727A: Global MASTER-Net observations report
  36. GRB 240727A: Swift/UVOT detection
  37. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  38. GRB 240727A: NOT optical observation
  39. GRB 240727A: JinShan optical upper limits
  40. GRB 240727A Bassano Bresciano Observatory upper limit
  41. GRB 240727C: AstroSat CZTI detection of a long burst
  42. GRB 240727A: Swift-XRT refined Analysis
  43. Fermi GRB 240726A: Global MASTER-Net observations report
  44. GRB 240727A: Enhanced Swift-XRT position
  45. GRB 240727B: Fermi GBM Observation
  46. GRB240529A: VIRT optical transient detection
  47. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  48. GRB 240726A: SVOM/GRM observation
  49. GRB 240726B: AstroSat CZTI detection of a short burst
  50. GRB240727A: Skynet Optical Afterglow Observations
  51. GRB 240727A: TRT optical afterglow detection
  52. GRB 240727A: Swift detection of a burst
  53. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  54. Fermi-LAT gamma-ray observations of IceCube-240725A
  55. Swift Trigger 1244778 is not a GRB
  56. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  57. GRB 240720A: Swift-BAT refined analysis
  58. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  59. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  60. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  61. Fermi-LAT gamma-ray observations of IceCube-240721A
  62. GRB 240720B: SVOM/GRM observation
  63. GRB 240720B: AstroSat CZTI detection of a short burst
  64. GRB 240718A: Fermi GBM Observation
  65. GRB 240718A: SVOM/GRM observation
  66. GRB 240718A: BALROG localization (Fermi Trigger 742976945 / GRB 240718270)
  67. GRB 240712A: Swift-BAT refined analysis
  68. GRB 240716A: GECAM-B detection of a long burst
  69. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  70. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  71. GRB 240715A: Swift/UVOT observations of the XRT sources.
  72. GRB 240715A: Swift-XRT observations
  73. GRB240713A: Swift/UVOT Upper LImits
  74. EP240708a: X-ray follow-up observations with Swift/XRT
  75. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  76. GRB 240713A: Swift-XRT observations
  77. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  78. GRB 240712A: Swift-XRT refined Analysis
  79. GRB 240713A: LAST optical upper limit
  80. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  81. Fermi GRB 240715A: Global MASTER-Net observations report
  82. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  83. GRB240715A: GRANDMA Optical Upper Limits
  84. GW s240422ed: Swift UVOT follow-up
  85. GRB 240712A: Swift/UVOT Upper Limits
  86. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  87. The EP-WXT source triggered on July 14th is likely a flaring star
  88. GRB 240713A: J-band upper limit from WINTER
  89. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  90. GRB 240713A: JinShan optical upper limits
  91. GRB 240713A: OHP/T120 optical upper limit
  92. GRB240713A: Optical upper limit with Kinder observations
  93. Fermi Sub-threshold Observation of GRB240713A
  94. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  95. EP240708a: GSP optical upper limit
  96. GRB 240712A: Swift detection of a burst
  97. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  98. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  99. Fermi GRB 240710A: Global MASTER-Net observations report
  100. EP240708a: NOT optical observations

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