Skip to main content
Circulars over Kafka event name backfill. See news and announcements

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"

6096 results found.

  1. GRB071021 : CFHT Ks-band observation
  2. GRB 071025: I-detection, R-dropout?
  3. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  4. GRB 071021: Swift-XRT Team refined analysis
  5. GRB 071020, Swift-BAT refined analysis
  6. GRB 071018: Swift-XRT observation
  7. GRB 071017 - Swift XRT observations
  8. GRB 071013: 3rd TLS Epoch - constraints on variability
  9. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  10. GRB 071011: Swift-XRT refined analysis
  11. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  12. GRB 071011, Optical afterglow
  13. GRB 071010: Swift-XRT observation
  14. GRB071008: Swift-XRT observation
  15. GRB 071010: Keck Observations of the Afterglow
  16. GRB 071003: XRT refined analysis
  17. GRB070920A: MAGIC telescope GeV observation
  18. GRB 070810B: further XRT analysis
  19. GRB 071003: Possible rebrightening
  20. GRB 071003: Swift XRT position
  21. GRB 071003 Optical observations
  22. GRB 071001: Swift-XRT Team refined analysis
  23. GRB070925: Swift-XRT Position
  24. GRB 070920B: XRT observations
  25. GRB 070923: Galaxies within BAT localization
  26. INTEGRAL ToO observations of SGR1806-20
  27. GRB 070917: Confirmation of the X-ray afterglow
  28. GRB 070920, Swift-BAT refined analysis
  29. GRB 070917: Swift-XRT observations
  30. GRB 070917: R band observations
  31. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  32. GRB 070911: PAIRITEL IR Observations
  33. GRB 070911: Swift XRT refined analysis
  34. GRB 070731: Swift/UVOT Upper Limit
  35. IPN Localization of GRB 070821 (long, very bright)
  36. GRB 070810B: XRT refined analysis
  37. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  38. GRB 070810: Swift-XRT Team Refined Analysis
  39. GRB 070809: Swift-XRT refined analysis
  40. GRB 070805: Swift XRT initial analysis.
  41. GRB 070724B: Swift-XRT afterglow confirmation
  42. GRB 070802: Swift-XRT refined analysis
  43. GRB 070802: GROND J band candidate
  44. GRB 070729: Swift-XRT refined analysis
  45. GRB 070729: Magellan NIR Observations
  46. GRB 070724: P60 and Gemini Observations
  47. GRB 070724: Swift-XRT Team refined analysis
  48. GRB 070721A: Swift/XRT refined analysis
  49. GRB 070616: No Evidence for I Band Afterglow
  50. GRB 070714A: Swift XRT refined analysis
  51. GRB070714B: Swift-XRT refined analysis
  52. GRB 070707: Swift-XRT follow-up observations
  53. Swift XRT observation of GRB 070707
  54. GRB 070628: Swift XRT refined analysis
  55. GRB070621: Swift XRT refined analysis
  56. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  57. GRB 070616: Swift XRT refined circular
  58. SWIFT J195509.6+261406 (GRB 070610): further observations
  59. GRB 070612B: Swift-XRT refined analysis
  60. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  61. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  62. GRB 070610: Swift-XRT refined analysis
  63. GRB 070611: Swift-XRT refined analysis
  64. GRB 070611; Swift-XRT position
  65. GRB 070610; Swift-XRT position
  66. GRB 070529: Swift-XRT refined analysis
  67. GRB 070521: Swift-XRT refined analysis
  68. GRB 070521: Keck imaging
  69. GRB070521: Gemini Observations
  70. GROND upper limits of GRB 070521
  71. GRB 070520B: Swift-XRT refined analysis
  72. GRB 070520A: Swift-XRT refined analysis
  73. GRB 070518: Swift-XRT refined analysis
  74. RHESSI Spectrum of GRB070508
  75. GRB 070508: Swift-XRT refined analysis
  76. GRB070412: MAGIC telescope GeV observation
  77. GRB 070429A: Swift XRT further analysis
  78. GRB 070420: Swift XRT refined analysis
  79. GBR 070419A: Swift/XRT refined analysis
  80. GRB 070419B: Swift XRT refined analysis
  81. GRB 070419A: Optical and IR observations with KANATA
  82. GRB 070418: Optical and IR observations with KANATA
  83. GRB 070406: Swift XRT refined analysis
  84. GRB 070411: Swift-XRT refined analysis
  85. GRB 070406: Swift XRT team further analysis
  86. Suzaku ToO observation of SGR 1806-20
  87. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  88. GRB 070406: Gemini South Imaging and XRT analysis
  89. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  90. GRB 070406: SARA upper limit
  91. GRB 070330: Swift-XRT refined analysis
  92. Konus-Wind observation of GRB 070328
  93. GRB 070328: Swift/XRT Refined Analysis
  94. GRB070208: optical observations
  95. GRB 070318: Gemini + Magellan spectra
  96. GRB070318: Swift-XRT refined analysis
  97. GRB 070311: Swift-XRT refined analysis
  98. GRB 070125: Chandra X-ray Confirmation of Jet Break
  99. GRB 070125: X-ray light curve analysis
  100. GRB 070306: XRT Team Refined Analysis

Advanced

Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit USA.gov