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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"

18335 results found.

  1. GRB 031203: Apparent Spectral Break
  2. GRB031203: Planned XMM-Newton observation II
  3. GRB 031203: IR REM Observations
  4. GRB031203: Optical Observations
  5. GRB 031203 XMM-Newton observation
  6. GRB031203: Planned XMM-Newton observation
  7. GRB 030329: Planned XMM-Newton Observation
  8. GRB 031111B (= H2925) : Kyoto Optical Observation
  9. GRB 031111, optical observations
  10. XRF031109 (=H2919): A very long XRF localized by HETE
  11. IPN triangulation of GRB031108 (large error box)
  12. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  13. GRB030929/SN2003jd association unlikely based on IPN localiztion
  14. IPN triangulation of GRB031027 (small error box)
  15. Lulin optical follow-up observations of GRB031026
  16. IPN triangulation of GRB031024 (single error box)
  17. XRF 030824: additional observations at CFHT
  18. XRF 030723: Subaru Optical Observations
  19. XRF 030824: Early follow-up observation at Kiso observatory
  20. XRF 030723: Detection of the likely host galaxy
  21. IPN triangulation of GRB030919 (large error box)
  22. GRB030913: Subaru Optical Observations
  23. GRB 030913, optical candidate
  24. GRB 030913, BOOTES observations
  25. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  26. XRF030824: Optical observations
  27. IPN triangulation of GRB030903 (large error box)
  28. IBAS detection of bursts from SGR 1806-20
  29. Radio Observations of SGR1806-20
  30. GRB030823: optical observation at Tokyo Tech
  31. Lulin follow-up observations of GRB030823
  32. GRB 030817 = H2808 TAROT optical observations
  33. SGR 1808-20 (=H2802): A Possible new SGR
  34. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  35. XRF030723, BVRcIc field photometry update
  36. IPN triangulation of GRB030801 (large error box)
  37. GRB021206 optical counterpart upper limit
  38. IPN triangulation of GRB030726 (large error box)
  39. XRF030723 Radio Observations
  40. XRF 030723: confirmation of fading optical counterpart
  41. XRF030723(=H2777): Chandra Observations
  42. GRB030723: Upper limits from historical observations
  43. XRF030723: Palomar observations and proposed counterpart
  44. XRF030723, BVRcIc field photometry correction
  45. XRF030723, ROTSE-III Early Observations
  46. XRF030723, BVRcIc field photometry
  47. XRF 030723, optical observations
  48. XRF030723, optical observations
  49. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  50. SGR 1806-20, submm observations
  51. RXTE PCA Observations of SGR1806-20 Region
  52. GRB030329: Subaru Optical Spectroscopy
  53. GRB030329, optical observation in May
  54. IPN triangulation of GRB030626 (single large error box)
  55. IPN triangulation of GRB030626 (two large error boxes)
  56. HETE detection of burst from SGR1806-20
  57. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  58. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  59. GRB 030528: tentative NIR counterpart
  60. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  61. GRB030528, BVRI field photometry
  62. GRB030329, SPM optical observations
  63. GRB030528(=H2724): Revised SXC Localization
  64. GRB 030528 Bisei optical observation
  65. GRB 030528 (=H2724) Kyoto optical observation
  66. GRB 030329 Optical Observations
  67. GRB 021004: HST observations
  68. GRB030324: Further Observations of the Candidate Optical Afterglow
  69. HETE GRB030329, correction to Rc Observations in Loiano
  70. GRB 030329: Optical limit (contemporaneous imaging)
  71. IPN triangulation of GRB030509 (single error box)
  72. GRB030429, refiend optical brightness
  73. GRB030418, BVRcIc field photometry
  74. GRB030429, BVRcIc field photometry
  75. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  76. GRB030329: RTT150 optical observations and upper limit for a host
  77. GRB030329: RTT150 optical observations and upper limit for a host
  78. GRB 030429: redshift from VLT spectroscopy
  79. GRB030501: TAROT candidate afterglow present in archival images
  80. GRB 030429: confirmation of afterglow candidate
  81. GRB 030329 Oprical observations in Rozhen observatory
  82. GRB030329, SPM optical observations
  83. GRB 030329, the review of the sky area in plate archive (1950-1998)
  84. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  85. GRB030329: optical polarization
  86. GRB030329, optical observation
  87. MASTER:optical observations GRB030418
  88. MASTER:optical observations probable GRB030414
  89. GRB030418: Upper limits from recent and historical observations.
  90. GRB030418: Kiso near infrared observations
  91. GRB030329: Optical Observations
  92. OT GRB 030329: early spectrum
  93. GRB030329, optical position
  94. Kiso observation of the GRB030329 at April 6
  95. GRB 030329, color evolution
  96. GRB030328, UBVRcIc field photometry
  97. GRB 030329 Optical observations
  98. GRB030329: Kiso B and R band observations
  99. SDSS 0.5m PT observations of GRB030329 (correction)
  100. SDSS 0.5m PT observations of GRB030329

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