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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3035 results found.

  1. GRB 240730A: Swift-XRT refined Analysis
  2. GRB 240715A: Swift-XRT afterglow detection
  3. GRB 240727B: Swift-XRT observations
  4. GRB 240727A: Swift-XRT refined Analysis
  5. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  6. GRB 240715A: Swift/UVOT observations of the XRT sources.
  7. GRB 240715A: Swift-XRT observations
  8. GRB240713A: Swift/UVOT Upper LImits
  9. GRB 240713A: Swift-XRT observations
  10. GRB 240712A: Swift-XRT refined Analysis
  11. The EP-WXT source triggered on July 14th is likely a flaring star
  12. GRB240713A: X-ray follow-up observation with EP-FXT
  13. EP240703c: EP-WXT detection of an X-ray transient
  14. EP240618a: Swift/XRT upper limit
  15. EP240617a: tentative Swift/XRT detection of the afterglow
  16. GRB 240619A: Swift-XRT probable afterglow detection
  17. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  18. GRB 240615A: Swift-XRT observations
  19. GRB 240606B: Swift-XRT afterglow detection
  20. Swift Trigger 1235109: a possible GRB 240606A
  21. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  22. Swift Trigger 1232465: consistent with noise
  23. The EP-WXT source triggered on June 1st is likely a flaring star
  24. GRB 240529A: Swift-XRT refined Analysis
  25. GRB 240527B: Swift-XRT afterglow detection
  26. GRB 240523A: Swift-XRT refined Analysis
  27. EP240518a: possibly identified with a flare star by EP-FXT
  28. GRB 240516A: Swift-XRT refined Analysis
  29. GRB 240513A: Swift-XRT observations
  30. GRB 240511A: Swift-XRT refined Analysis
  31. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  32. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  33. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  34. XMM-Newton observation of EP240426a
  35. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  36. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  37. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  38. LXT240402A/GRB240402B: Chandra X-ray detection
  39. GRB 240415B: Swift-XRT observations
  40. GRB 240415A: Swift-XRT refined Analysis
  41. GRB 240421B: Swift-XRT refined Analysis
  42. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  43. GRB240418A - Candidate afterglow from NIRES
  44. GRB 240419B: Swift-XRT refined Analysis
  45. GRB 240419A: Swift-XRT refined Analysis
  46. GRB 240418A: Swift-XRT refined Analysis
  47. EP240414a: EP-FXT follow-up observation
  48. LXT 240402A/GRB 240402B: Swift follow-up observations
  49. GRB 240414A: Swift-XRT refined Analysis
  50. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  51. GRB 240411B: Swift-XRT refined Analysis
  52. Fermi GRB 240407A: Global MASTER-Net observations report
  53. LXT 240402A: EP-FXT detection of the X-ray afterglow
  54. X-ray transient EP 240315a: Second epoch Chandra observations
  55. X-ray transient EP 240315a: Chandra observations
  56. GRB 240225B: Swift-XRT afterglow detection
  57. GRB 240215A: Swift-XRT afterglow detection
  58. GRB 240225B: Swift-XRT observations
  59. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  60. GRB 240222A: Swift-XRT refined Analysis
  61. GRB 240218A: LBT H-band detection
  62. Konus-Wind detection of GRB 240218A
  63. GRB 240218A: Swift-XRT refined Analysis
  64. Fermi GRB 240216A: Global MASTER-Net observations report
  65. GRB 240128A: Further Swift-XRT observations
  66. GRB240204A: Swift/UVOT Upper Limits
  67. GRB 240128A: Swift-XRT observations
  68. GRB 240122A: Swift/UVOT Upper Limits
  69. GRB 240123A: Swift-XRT refined Analysis
  70. GRB 240122A: Swift-XRT afterglow detection
  71. GRB 240118A: Swift-XRT afterglow detection
  72. GRB 240112C: Swift-XRT refined Analysis
  73. GRB 231220A: Swift-UVOT upper limit
  74. GRB 240101B: Swift-XRT refined Analysis
  75. GRB 240102A: Swift-XRT refined Analysis
  76. GRB 240101B: Swift/UVOT Upper Limits
  77. GRB 240101A: Swift-XRT refined Analysis
  78. GRB 231230A: Swift-XRT refined Analysis
  79. Fermi trigger No 725592555: Global MASTER-Net observations report
  80. GRB 231222B: Swift-XRT afterglow detection
  81. GRB 231220A: Swift-XRT follow-up observations
  82. GRB 231216A: Swift-XRT refined Analysis
  83. GRB 231215A: Swift-XRT refined Analysis
  84. GRB 231214A: Swift-XRT refined Analysis
  85. GRB 231210B: Swift-XRT refined Analysis
  86. GRB 231205B: Swift-XRT refined Analysis
  87. GRB 231129C: Swift-XRT afterglow detection
  88. GRB 231129B: Swift-XRT observations
  89. GRB 231129C: Swift-XRT observations
  90. GRB 231129A: Swift-XRT refined Analysis
  91. GRB 231123C: Insight-HXMT/HE detection
  92. GRB 231115A: XMM-Newton observation
  93. GRB 231117A: GTC Near-Infrared Observations
  94. GRB 231117A: Swift-XRT refined Analysis
  95. GRB 231118A: Swift-XRT refined Analysis
  96. GRB 231115A: NuSTAR Follow-Up Observations
  97. GRB 231115A: Swift-XRT and Swift-UVOT observations
  98. GRB 231115A: archival Chandra X-ray observations
  99. GRB 231110A: Swift-UVOT Upper Limits
  100. GRB 231111A: Swift-XRT refined Analysis

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