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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"

32508 results found.

  1. GRB 240727A: KAIT Optical Afterglow Candidate
  2. GRB 240726A: AstroSat CZTI detection of a short burst
  3. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  4. Fermi-LAT gamma-ray observations of IceCube-240725A
  5. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  6. GRB 240720A: Swift-BAT refined analysis
  7. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  8. Fermi-LAT gamma-ray observations of IceCube-240721A
  9. Fermi Gamma-ray Burst Monitor trigger 743243582/240721356 (GRB 240721A) is not a GRB
  10. GRB 240720B: SVOM/GRM observation
  11. Fermi GRB 240720A: Global MASTER-Net observations report
  12. GRB 240720A: AstroSat CZTI detection
  13. GRB 240720A: Fermi GBM observation
  14. Konus-Wind detection of GRB 240718A
  15. GRB 240713A: SVOM/GRM observation
  16. Fermi GRB 240718A: Global MASTER-Net observations report
  17. GRB 240718A: Fermi GBM Observation
  18. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  19. GRB 240718A: Fermi-LAT Detection
  20. GRB 240718A: SVOM/GRM observation
  21. GRB 240712A: Swift-BAT refined analysis
  22. GRB 240716A: GECAM-B detection of a long burst
  23. GRB 240715A: Swift/UVOT observations of the XRT sources.
  24. GRB240713A: Swift/UVOT Upper LImits
  25. EP240708a: X-ray follow-up observations with Swift/XRT
  26. GRB 240715A: GECAM-C detection of a short burst
  27. Konus-Wind detection of GRB 240715A
  28. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  29. GRB 240713A: Swift-XRT observations
  30. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  31. SVOM/GRM In-Flight Trigger of GRB 240715A
  32. GRB 240713A: LAST optical upper limit
  33. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  34. GRB 240715A: Swift ToO observations
  35. Fermi GRB 240715A: Global MASTER-Net observations report
  36. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  37. GRB 240715A: Fermi GBM Observation
  38. GRB 240712A ATCA radio observations
  39. GRB240715A: GRANDMA Optical Upper Limits
  40. IPN triangulation of GRB 240715A (short)
  41. GRB 240712A: Swift/UVOT Upper Limits
  42. EP-WXT flaring star and the optical flaring activity during its decay phase
  43. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  44. GRB 240713A: Tiled Swift observations
  45. GRB 240713A: J-band upper limit from WINTER
  46. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  47. GRB 240713A: JinShan optical upper limits
  48. GRB 240713A: OHP/T120 optical upper limit
  49. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  50. GRB240713A: X-ray follow-up observation with EP-FXT
  51. GRB240713A: Optical upper limit with Kinder observations
  52. Fermi Sub-threshold Observation of GRB240713A
  53. EP240708a: GSP optical upper limit
  54. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  55. EP240708a: KAIT optical upper limit
  56. Fermi GRB 240710A: Global MASTER-Net observations report
  57. EP240708a: NOT optical observations
  58. EP240708a: SVOM/C-GFT optical upper limit
  59. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  60. EP240708a: Optical upper limits with Kinder observations
  61. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  62. EP240703b: GSP optical upper limit
  63. EP240703b: TRT optical upper limits
  64. EP240703a: TRT further optical observation
  65. EP240702a: TRT optical upper limits
  66. Konus-Wind detection of GRB 240627A
  67. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  68. EP240703a and EP240703b: Swift/XRT upper limits
  69. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  70. EP240703a: KAIT optical upper limit
  71. EP240703a: BTA observations
  72. EP240703c: Kinder optical follow-up and Swift XRT observations
  73. EP240703a: Liverpool Telescope optical follow-up observations
  74. EP240703a/GRB 240703A: TRT optical candidate likely not real
  75. EP240703a: Kinder optical follow-up observations
  76. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  77. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  78. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  79. IPN triangulation of GRB 240627A
  80. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  81. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  82. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  83. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  84. EP240702a: Swift/XRT upper limit
  85. EP240702a: GSP optical upper limit
  86. Fermi GRB 240702A: Global MASTER-Net observations report
  87. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  88. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  89. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  90. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  92. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  93. Fermi GRB 240629A: Global MASTER-Net observations report
  94. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  95. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  96. IPN triangulation of GRB 240619C
  97. GRB 240627A: NuSTAR Detection of the long GRB
  98. GRB 240615A: SAI CMO J- band observations
  99. EP240626a: Montarrenti Observatory optical upper limit
  100. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate

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