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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"

24999 results found.

  1. GRB 030328: OT photometry
  2. GRB030328: optical spectroscopy at TNG
  3. GRB030328: optical photometry at the TNG
  4. VLT spectra of GRB 030328
  5. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  6. GRB 030328: Optical observations
  7. GRB030324 optical observation
  8. GRB030131, BVRcIc field photometry
  9. Possible GRB030323 localized by INTEGRAL
  10. GRB030323: Detection on 2003/03/24
  11. IPN triangulation of GRB030326 (single small error box)
  12. IPN triangulation of GRB030325 (two small error boxes)
  13. GRB030323: V, R, I photometry
  14. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  15. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  16. VLT/FORS2 spectra of GRB 030323
  17. GRB030323, optical observations
  18. GRB030324, BVRcIc field photometry
  19. GRB030323, BVRcIc field calibration
  20. IPN triangulation of GRB030320 (small error box)
  21. Possible GRB 030320 localized by INTEGRAL
  22. IPN triangulation of GRB030306 (single small error box - REVISED)
  23. IPN triangulation of GRB030306 (single small error box)
  24. IPN triangulation of GRB030306 (two small error boxes)
  25. GRB030226, BVRc observations
  26. Chandra detection of the X-ray afterglow of GRB 030226
  27. GRB030227: Kiso optical upper limit
  28. GRB030227, BVRcIc field photometry
  29. GRB030226, BVRcIc field calibration
  30. GRB 030228, optical observations
  31. GRB 030227: Confirmed Optical Afterglow (S1-A)
  32. GRB 030227: fading of candidate optical afterglow 'S1-A'
  33. GRB030227:Optical observations
  34. GRB 030227, possible optical counterpart of XMM-Newton source
  35. GRB030227 - faint tentative OT candidate
  36. GRB 030226, optical observations
  37. XMM-Newton observation of GRB030227
  38. GRB030227: Kiso optical observations
  39. GRB 030227: Kyoto optical observation
  40. GRB 030226, optical light curve
  41. GRB030227 localized by INTEGRAL
  42. GRB 030226 : Predicted light curve
  43. GRB030226: ESI spectroscopy
  44. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  45. GRB 030226 simultaneous optical observations
  46. GRB 030226, optical observations
  47. GRB030226: Optical decay index
  48. GRB 030226 Optical Spectra and R,I,z' Imaging
  49. GRB: Non-Referencing of GCN Circulars.
  50. IPN triangulation of GRB030217 (small error box)
  51. GRB 030131: marginal optical detection
  52. GRB 030204: Optical Observations
  53. GRB030204 field photometry
  54. GRB020819: Kiso R and I band observations
  55. GRB030131: Candidate Optical Afterglow
  56. IPN triangulation of GRB030204 (small error box)
  57. GRB 030131, optical observations
  58. GRB 030131: afterglow candidate
  59. GRB 030115, late-time optical observations
  60. GRB030131: corrected INTEGRAL position
  61. GRB 020819: Host galaxy at Radio Position
  62. IPN triangulation of GRB030131
  63. GRB 030131 optical observations
  64. GRB 030131 optical observations
  65. A long GRB detected by INTEGRAL
  66. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  67. GRB 030115, simultaneous observations by BOOTES-1
  68. GRB 030115: IR observations with IRSF/SIRIUS
  69. IPN triangulation of GRB030115C (large error box)
  70. GRB030115, afterglow candidate
  71. GRB 021211: R-band observations at late-time
  72. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  73. GRB 030115 : Possible IR counterpart
  74. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  75. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  76. GRB 030115: APO Optical Observations
  77. Information about where HETE will be pointing
  78. VLT spectroscopy of the probable host of GRB 021211
  79. IPN triangulation of GRB030101 (two large error boxes)
  80. GRB 021211: Probable Host and Underlying Supernova
  81. GRB 021112: Evidence for Another Dark Optical Afterglow
  82. GRB 021219: OSN optical observations
  83. GRB021219, optical observations
  84. GRB021219, optical observation by MASTER
  85. VLT spectra of GRB 021211 revisited
  86. GRB021219: a long GRB localized by INTEGRAL
  87. GRB021211: APO optical observations
  88. XRF 020903 : HST observations
  89. GRB 021201: Optical Observations
  90. GRB 021211: CTIO observations
  91. GRB021211, BVRI field photometry
  92. GRB021211: Optical observations in CrAO
  93. GRB 021211, optical observations
  94. GRB021211: Kiso Observations
  95. GRB 021201, optical observations
  96. GRB021211: Optical observations
  97. GRB 021201 (short/hard), NOT observations
  98. SUB-MM SEARCH FOR GRB 021211
  99. Chandra observation of the IPN error box of GRB021201 (short/hard)
  100. GRB 021211, R- and I-band observations

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