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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"

43604 results found.

  1. GRB 990510: BeppoSAX/GRBM observations
  2. GRB990510 optical observations
  3. GRB990510
  4. GRB 990510 optical observations
  5. GRB 990510 optical observations
  6. GRB990510: NFI X-ray source
  7. GRB 990510 optical observations
  8. IPN localization of GRB990510
  9. GRB 990506 Radio Observations
  10. GRB 990123, optical monitoring
  11. GRB 990506: BATSE Observations
  12. GRB 990506, optical observations
  13. GRB 990510: Final BeppoSAX-WFC Coordinates
  14. GRB 990506, Optical Observations
  15. GRB 990506, optical observations
  16. GRB990506 observation plan
  17. Refined IPN error box for GRB990506
  18. GRB 990506: Limits on the possible optical transient
  19. GRB 990506, armchair astronomy
  20. GRB 990506, optical observations from +1 to +3 hours
  21. GRB 990506, optical observations
  22. GRB990506 Optical observations
  23. GRB990506 observation plan
  24. New IPN/RXTE error box for GRB990506
  25. IPN localization for GRB990506
  26. GRB 970228: Redshift and properties of the host galaxy
  27. GRB981220 VLBA observations
  28. GRB980425 Optical observations of exponential decline at late time
  29. GRB990323 PRECISE IPN POSITION
  30. GRB990321 IPN TRIANGULATION
  31. GRB 990316 Optical Observations
  32. GRB 990316, Radio observations
  33. GRB 990316, Optical observations
  34. GRB990316, Optical observations
  35. GRB 990316 optical observations
  36. GRB990316: simultaneous optical observation
  37. GRB990316 - Optical null results
  38. ASM/IPN error box for GRB 990308 (BATSE #7457)
  39. GRB990308 not a new SGR
  40. GRB 990308a and GRB 990308b
  41. GRB990308 (Trig. 7457), optical observations
  42. GRB990308, Possible new SGR~0209+70
  43. GRB981220, IPN localization
  44. GRB 981220, radio observations
  45. GRB 990123, Field Photometry
  46. GRB 990217, radio observations
  47. BATSE Resumes Normal Operations
  48. BATSE Flight Anomaly
  49. GRB990217: BeppoSAX/GRBM data
  50. Optical Observations of GRB990217
  51. GRB990123: Caltech STIS Photometry and Images
  52. GRB990123 observations
  53. GRB990217, WFC position
  54. GRB990123, Optical Observation
  55. GRB 990123: Discovery of the Probable Host Galaxy
  56. GRB 990123: Reduced HST Images
  57. For Immediate Posting to GCN - HST Data GRB 990123 Available
  58. GRB19990123 observations
  59. GRB 990123: Updated Keck Spectroscopy Results
  60. GRB981220, field photometry
  61. GRB 990123 NOT Spectrum Update
  62. GRB990123, Optical observation
  63. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  64. GRB 990123: Publicly available reduced HST images
  65. GRB990123, Upcoming HST Service Observations
  66. GRB990123, 15-GHz limits
  67. GRB 990123: New Constraints on Possible Foreground Galaxies
  68. GRB990123 Optical Observations
  69. GRB990123, Probability of gravitational lensing
  70. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  71. GRB 990123: Continued Radio Observations
  72. GRB990123, Preliminary Lens Search Results
  73. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  74. On the Lensing Interpretation of GRB 990123
  75. Search for Potential Images of GRB 990123
  76. Search for Potential Images of GRB 990123
  77. GRB990123, Optical BVRI Observations
  78. GRB 990123: near-infrared observations.
  79. GRB990123, OSSE observations
  80. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  81. GRB990123: NIR Observation
  82. GRB990123, ASCA X-ray observation of afterglow
  83. GRB 990123 Optical Follow-Up
  84. GRB 990123: BATSE Observations
  85. GRB 990123 Keck Spectrum update
  86. GRB990123 IPN annulus
  87. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  88. GRB990123 Optical Observations
  89. GRB 990123 Spectroscopic Redshifts
  90. GRB 990123: New Optical Observations, Decay Measure
  91. GRB 990123 Optical Follow-Up
  92. GRB 990123: Possible Gravitationally Lensed Burst?
  93. GRB 990123 optical observations
  94. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  95. GRB 990123 radio observations
  96. GRB 990123, new radio source
  97. GRB990123 optical observations
  98. GRB990123, Optical observation
  99. GRB 990123: Optical Decay Slope
  100. GRB 990123 r-band photometry

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