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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"

16236 results found.

  1. EP240801a: BTA BVRI photometry
  2. Swift GRB 240805A: Global MASTER-Net observations report
  3. GRB 240805A: Swift-XRT refined Analysis
  4. GRB 240805B: Swift detection of a burst
  5. EP240801a: Continued optical observations at ZTSh (CraO)
  6. EP240804a: NOT optical counterpart detection
  7. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  8. EP240802a: Montarrenti Observatory optical upper limit
  9. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  10. EP240802A: Bassano Bresciano Observatory upper limit
  11. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  12. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  13. GRB 240802A: AstroSat CZTI detection of a long burst
  14. EP240801a: further SAO RAS optical observations
  15. EP240801a: optical observations at CrAO and AbAO
  16. EP240801a: Leavitt Observatory optical observations
  17. EP240801a: SAO RAS optical observations
  18. EP240801a: JinShan optical observations
  19. GRB 240727C: SVOM/GRM observation
  20. EP240801a: follow-up observation with LCOGT
  21. EP240801a: Kinder follow-up observations of the candidate counterpart
  22. EP240801a: GMG observation
  23. EP240801a: TRT optical counterpart detection
  24. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  25. GRB 240730C: AstroSat CZTI detection of a long burst
  26. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  27. GRB 240730A: Swift-XRT refined Analysis
  28. GRB 240730A: Swift/UVOT Upper Limits
  29. GRB 240730A: Enhanced Swift-XRT position
  30. GRB 240730A: Swift detection of a burst
  31. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  32. GRB 240727A: observations of optical counterpart.
  33. GRB 240727B: Swift-XRT observations
  34. GRB 240727A: Swift/UVOT detection
  35. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  36. GRB 240727A: NOT optical observation
  37. GRB 240727A: JinShan optical upper limits
  38. GRB 240727A Bassano Bresciano Observatory upper limit
  39. GRB 240727C: AstroSat CZTI detection of a long burst
  40. GRB 240727A: Enhanced Swift-XRT position
  41. GRB240529A: VIRT optical transient detection
  42. GRB 240726A: SVOM/GRM observation
  43. GRB 240726B: AstroSat CZTI detection of a short burst
  44. GRB240727A: Skynet Optical Afterglow Observations
  45. GRB 240727A: TRT optical afterglow detection
  46. GRB 240727A: Swift detection of a burst
  47. Swift Trigger 1244778 is not a GRB
  48. GRB 240720B: SVOM/GRM observation
  49. GRB 240720B: AstroSat CZTI detection of a short burst
  50. Swift GRB240720.02: Global MASTER-Net observations report
  51. GRB 240718A: SVOM/GRM observation
  52. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  53. GRB 240715A: Swift/UVOT observations of the XRT sources.
  54. GRB240713A: Swift/UVOT Upper LImits
  55. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  56. GRB 240712A: Swift-XRT refined Analysis
  57. GRB 240713A: LAST optical upper limit
  58. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  59. GRB 240712A ATCA radio observations
  60. GRB240715A: GRANDMA Optical Upper Limits
  61. GW s240422ed: Swift UVOT follow-up
  62. GRB 240712A: Swift/UVOT Upper Limits
  63. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  64. The EP-WXT source triggered on July 14th is likely a flaring star
  65. GRB 240713A: J-band upper limit from WINTER
  66. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  67. GRB 240713A: JinShan optical upper limits
  68. GRB 240713A: OHP/T120 optical upper limit
  69. GRB240713A: X-ray follow-up observation with EP-FXT
  70. GRB 240713B: AstroSat CZTI detection of a long burst
  71. GRB240713A: Optical upper limit with Kinder observations
  72. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  73. EP240708a: GSP optical upper limit
  74. GRB 240712A: Swift detection of a burst
  75. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  76. EP240708a: NOT optical observations
  77. EP240708a: SVOM/C-GFT optical upper limit
  78. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  79. EP240708a: Optical upper limits with Kinder observations
  80. EP240708a: EP-WXT detection of a fast X-ray transient
  81. EP240703b: TRT optical upper limits
  82. EP240703a: TRT further optical observation
  83. EP240702a: TRT optical upper limits
  84. IPN triangulation of GRB 240628B (short)
  85. EP240703c: Kinder optical follow-up and Swift XRT observations
  86. EP240703a: Liverpool Telescope optical follow-up observations
  87. EP240703a: Kinder optical follow-up observations
  88. EP240703c: EP-WXT detection of an X-ray transient
  89. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  90. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  91. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  92. EP240703b: EP-WXT detection of a fast X-ray transient
  93. EP240703a: EP-WXT detection of a fast X-ray transient
  94. EP240702a: EP-WXT detection of a fast X-ray transient
  95. IPN triangulation of GRB 240619C
  96. GRB 240615A: SAI CMO J- band observations
  97. EP240626a: Montarrenti Observatory optical upper limit
  98. EP240626a: EP-FXT detection of the X-ray emission
  99. EP240626a: EP-WXT detection of a fast X-ray transient
  100. GRB 240625A: Fermi GBM Observation

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