Языки

Supernova Light Curve Catalogues

ITEP-SAI Supernova Light Curve Catalogue (ISSLCC)



Sternberg Astronomical Institute Supernova Light Curve Catalogue

Help

  • 1: Find a parameter for a supernova

    This item allows you to search ISSLCC for parameters, which are necessary for the calculation of absolute magnitudes of supernovae (SN), such as visual magnitudes in maximum, redshift, distances, extinction, etc.

    The Input options.

    Input just the name of SN. Examples of permitted SN names: 1987A, 2000as. Press button "Submit".

    Results.

    When a search has returned successfully, the page comes with tables with all parameters for SN in ISSLCC.

    There are three tables per each parameter. The first table shows the adopted value of the parameter and its uncertainty.

    The next table lists all values of the parameter which are presented in ISSLCC.
    The column "Adopted?" shows whether the current value has been adopted ("1") or it has been averaged together with some other available values, presented in ISSLCC ("2" or "3"). The next column "Ids of values to be averaged" enumerates identifiers of values separated by commas. They correspond to the identifiers pointed out in the first column "Id". In the penultimate column "Ref.Id" the identifier of journal's reference is pointed out.The complete records of references are presented in the third table.

  • 2: Draw observable light curve of a supernova

    This item allows you to draw observable or observable fitted light curve of a supernova.

    The Input options.
    Input the name of SN from the first field, select the passband. Press button "Submit".

    Results.

    When your request has returned successfully, the page comes with two drawings of graphs with absolute and visual light curves and the two corresponding tables of values "dates-magnitudes". We do not take into account relativistic effects in calculating M_abs, and use formula: M_abs = m_vis - 25 * log (Dist_75) - R * E(B-V)_tot . Distances were calculated with the value of Hubble constant H0 = 75 km/(s Mpc). Standard values R were taken from Cardelli et al., 1989. So user of ISSLCC himself should do corrections for values of H0, R, and should take into account relativistic effects if he would prefer.

  • 3: Qualification of a supernova to be used in the program of
    calculation of its nearest theoretical light curves.

    Select this option to check an availability and quality of necessary data on supernova observable light curve for calculation its nearest theoretical light curves. This find is realized inside the item N4 of the main ISSLCC menu.

    The Input options.

    Input the name of supernova and select the passband. Press button "Submit" .

    Results.

    When your request has returned successfully, the page comes with two tables which show the presence of necessary parameters: distance, extinction, maximum date and magnitude in the first table, and light curve points in the given passband in the second one. If all parameters exist, then the absolute observable light curve of SN could be calculated. This possibility is shown by green light of all corresponding table fields. If there is just a small part of SN light curve, up to just several days after light curve maximum, then user should set the smaller value of the corresponding parameter "Rel.day limit" in the item N4 of the main ISSLCC menu.

    The kinds of light curve may be observable or fitted ones. The program code in the next item (N4) uses the observable fitted light curve. So for the calculations of the SN absolute observable light curve there should exist necessary data: distance, extinction, JD (max), Mag(max) and light curve points (dates and magnitudes).

  • 4: Find nearest theoretical light curves to the test curve

    This item (N4) allows you to find nearest theoretical light curves to the test curve. This test curve may be either 1) an observable light curve or 2) a theoretical ones, taken from inside ISSLCC or given to computer code by user.

    The Input options.

    The first field of the item N4 provides three possibilities:

    MODE 1) To get a test light curve from user, MODE 2) to select a test light curve from a set of theoretical light curves which have been already presented in ISSLCC and automatically calculate the absolute observable light curve of SN,
    MODE 3) to do the same, but to calculate the absolute observable light curve of SN with parameters, given by user of ISSLCC.

    Also input SN name (required for (MODE 2),(MODE 3)) and select the passband
    (required for all modes). Set the Relative day limit, which shows the duration of light curves. The values of Relative day limit up to 100 days are permitted for this demo version. The Relative day step parameter is automatically set to
    10 days, which shows notes on time scale where the values of SN and theoretical model brightnesses are compared with one to another. Algorithm of comparison of light curves uses the method of cluster analysis for breaking up of objects on groups, so you should set up the number of groups. The parameter to set this value is "Level of hierarh".

    The computer code himself could calculate the SN absolute observable light curve or user could add the value of Modulus to visual observable light curve to receive the absolute one. In the latter case for MODE 3 user should point out the value of this Module in the field "Value to add" .

    Also there is a possibilty to calculate the SN absolute observable light curve with parameters, given to computer code by user. In the case user himself should fill out the corresponding fields of the form "Distance", "Color excess", "R". The formula for calculation is M_abs = m_vis - 25 * log (Dist_75) - R * E(B-V)_tot .

    Also for MODE 3 the computer code himself could calculate the date of light curve maximum. For the case just set the option "Onset on maximum" to value "Yes". If user wants to calculate the SN absolute observable light curve with his own value of maximum, he should set the option "Onset on maximum" to value "No" and point out the value of maximum in the corresponding fields "Offset, days" and "Offset, mags". The "Offset, days" is the difference between the julian date of first light curve point (first observation) and the
    julian date of maximum. The value could change in the interval ( (-1)* (julminimum-julmaximum) , 0 ) days and is always below zero.

    The changing the scale of graph is possible with a help of parameters "X-axis Window for graph" and "Y-axis Window for graph", which show parts of graph in percents to be drawn in low scale for detailed study. For this option one should set "Crop Graph" to the value "Yes".

    For some SN its light curves do not begin at or before the date of maximum, for example SN 1993J in passband B" is the case. The first observation in "B" was made on relative day 1.42 after light curve maximum. So the fitting does not go successfully when the parameter "Copy a point near maximum to the maximum" is not be set to the value "Yes" and the parameter Days is not be set to 1.42 day (to 0 or 1 day). So set the parameter Days to at least 2 days and then computer code will create an artificial point of light curve at light curve maximum. This operation will lead the computer code to run successfully without an error.

    For MODE 1 user could input his absolute light curve into the text field "Textfield for user's light curve".There should be the pairs of values "relative day - absolute magnitude" to represent light curve.The relative day = 0 should correspond to the light curve maximum value. The maximal length of this field is 500 symbols.

    Results.

    When your request has returned successfully, the page comes with many tables, graphs and the dendrogram.

    In the first table there is the list of values of parameters, used in calculations. The next table is the data on the SN visual light curve, together with the references of light curve points. These points were used for calculation of smoothed (observable fitted) light curve.

    The next table shows the points of smoothed light curves of models and test (observable or user's) light curve (magnitudes, days after max), used in calculations with help of cluster analysis. Then the tables with relative brightnesses were presented. The relative brightness is the value in percent in the scale of maximal and minimal brightness for every relative day after light curve maximum.

    The computer code breaks light curves into groups, named clusters. So the average values of relative brightness for clusters are also presented in the next table. Then go lists of objects (models) inside each cluster and cluster membership.

    The next table shows the theoretical light curves which are nearest to the tested (observable or user's) light curves. Then goes the dendrogram of cluster analysis which represents the relationship between clusters of objects.

    Finally go the graph section of results. The graphs show all three nearest theoretical light curves together with the tested light curve. For every nearest models there are set of the table and the graph pairs. These tables present the magnitudes of the nearest models and the tested curve for each day after maximum, the differences between magnitudes and the square of the differences between magnitudes which is the dissimilarity between light curves for each days. The sum of these dissimilarities for each day after maximum is the criteria for comparison of light curves, presented in the table with the list of nearest models and dissimilarities between theoretical and tested light curves.

    And the last two graphs show observable and observable fitted light curves for the tested light curve.

    Return to:


    (C) ITEP-SAI Supernova Study Collaboration. Moscow, Russia. 2006-2012.
    (C) Lomonosov Moscow State University, Sternberg Astronomical Institute Supernova Group, Moscow, Russia (MSU, SAI)
    Supported by grants of "Scientific Schools of Russia (3458.2010.2)", RFBR (10-02-00249)
    (C) Internet site space and support of Alikhanov Institute for Theoretical and Experimental Physics, Moscow, Russia (ITEP)