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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"

20522 results found.

  1. GRB040709 J,H-band observations
  2. GRB040624, optical observations
  3. XRF 040701, optical observations
  4. GRB 040624: optical observations
  5. Optical Observations of GRB040624
  6. GRB 040624: optical observations at TNG and VLT
  7. GRB 040624: R-band observations
  8. GRB 040624, optical observations
  9. GRB 030329: Rebrightening of hyperluminal ejecta.
  10. GRB040511: Retraction of redshift identification
  11. SGR 1806-20: no IR variability of the proposed counterparts
  12. SGR 1806-20, potential NIR counterpart
  13. GRB 040606: Optical observations
  14. GRB 040511: NIR observations with REM
  15. GRB 040511: Second Epoch Optical Observations
  16. GRB 040511: Optical observations
  17. GRB 040511: Optical Observations
  18. GRB040511: Optical Observations
  19. GRB040511: Optical Observations
  20. GRB040422: optical observations at Xinglong Observatory
  21. GRB040422: optical observations at CrAO
  22. GRB040422, optical observations at Loiano
  23. GRB040422: optical and NIR observations at the VLT
  24. GRB 040403, deep optical observations
  25. GRB 040403: Optical Observations
  26. GRB 040403 Optical Observations
  27. GRB 040403: Optical observations
  28. GRB 040403: optical observations
  29. GRB 040403: Optical Observations
  30. GRB040323: NIR Observations and Variable Object
  31. GRB 040228 Optical observations
  32. GRB 040223: Deep NIR NTT observations
  33. GRB 040223 : Optical observation (non-detection)
  34. GRB 040223, VLA observations
  35. GRB 040223: REM IJK Observations
  36. GRB031111, optical observations
  37. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  38. GRB031203: Chandra Observations
  39. GRB040106, follow-up radio observations
  40. GRB040106, Radio Observations
  41. GRB040106, likely optical afterglow
  42. GRB040106: Second Epoch Optical Observations
  43. GRB 031220: Optical observations of Chandra X-ray sources
  44. GRB040106: optical observations with REM+ROSS
  45. GRB 040106: Optical observations
  46. GRB031220: Palomar Observations
  47. GRB 031203 I-band monitoring
  48. GRB 2974 follow-up observations
  49. GRB 031203: SMARTS optical monitoring
  50. XMM-Newton Observations of GRB031203: Preliminary Images
  51. GRB 031203: Variable Radio Source
  52. GRB 031203: Magellan spectrum of possible GRB host
  53. GRB 031203: Deep NIR NTT & VLT observations
  54. GRB 031203: Radio detection
  55. GRB 031203: Further reports on December 4 observations
  56. GRB 031203: IR NTTobservations do not confirm REM detection
  57. GRB 031203: Apparent Spectral Break
  58. GRB 031203: IR REM Observations
  59. GRB031203: Optical Observations
  60. GRB 031203: Optical/IR SMARTS Observations
  61. GRB031111A, prompt optical observations
  62. GRB 031111, Radio observations
  63. GRB 031111: Optical observations
  64. GRB 031111, optical observations
  65. SN 2003jd (SN/GRB?) -- X-ray Observations
  66. XRF031109 (=H2919): A very long XRF localized by HETE
  67. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  68. Lulin optical follow-up observations of GRB031026
  69. SN 2003jd (SN/GRB?), Radio Observations
  70. GRB 031026: Further Ic Observations
  71. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  72. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  73. GRB 031026: Ic Observations
  74. GRB030329: radio observations at RT-22 (CrAO)
  75. XRF 030824: additional observations at CFHT
  76. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  77. IPN detection of continued activity from SGR1806-20
  78. XRF 030723: Subaru Optical Observations
  79. XRF 030824: observations at CFHT
  80. GRB030913: Subaru Optical Observations
  81. GRB 030913: ROTSE-3c Optical Observations
  82. GRB030913, candidate afterglow observations
  83. GRB 030913, optical candidate
  84. GRB030913: AAVSO optical observations
  85. GRB 030913, BOOTES observations
  86. GRB030913 (=H2849): Confirmation of the Flight Localization
  87. GRB030913 (=H2849): TAROT Observations
  88. Magellan Observations of GRB030725 (=H2779)
  89. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  90. XRF030824: Optical observations
  91. IBAS detection of bursts from SGR 1806-20
  92. Radio Observations of SGR1806-20
  93. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  94. XRF030824: Second-epoch Palomar observations
  95. XRF030824: optical observations
  96. GRB030823: optical observations
  97. GRB030823: Palomar observations
  98. XRF030824: Palomar observations
  99. RAPTOR observations of GRB030823
  100. Lulin follow-up observations of GRB030823

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