Variability Screening of Intermediate-Mass Black Hole Candidates

We realize that this programme will interrupt your own important science at the NOT. However, we rely entirely on the visiting astronomers as well as NOT staff to carry out the observations for us. Your co-operation is highly appreciated, and in return we offer co-authourship on any articles based on the observations you take. If you wish to be added as a co-authour, please notify us (wold@astro.uio.no) and provide your name and affiliation. The programme should take 15-20 min of your time per night. We are also grateful for any comments you may have regarding the information on this web page (email to wold@astro.uio.no).

We only use StanCam to ensure that we get a uniform set of observations and realiable variability measurements.

Abstract:
Almost every galaxy is thought to harbour a supermassive black hole. The black hole may play a crucial role for the evolution of a galaxy, for instance by regulating star formation via energetic outflows. Much can be learned from studying the relation between black holes and galaxies, but black hole mass measurements are extremely challenging if the mass is less than 10 million solar masses, or for galaxies beyond the Local Group. The only direct method applicable in this mass range utilizes temporal instead of spatial resolution. What cannot be resolved spatially even with extremely large telescopes can instead be resolved in the time domain using smaller telescopes like the NOT. With this programme we are monitoring a sample of quasars that are candidates for black holes in the intermediate-mass range. The ultimate aim is to measure their black hole masses using spectroscopic monitoring via so-called reverberation (echo) mapping.

Target information: 

Name: SDSS J114008.71+030711.4 Exposure time: 2 x 180 sec V-filter                          2 x 180 sec R-filter Coordinates: RA: 11:40:08.71  DEC: +03:07:11.4  (J2000.0) Magnitude: g = 17.3 Observing period: Apr + May + 1st half of June TCS catalogue: wold_p35.cat
Name: SDSS J115138.24+004946.4 Exposure time: 2 x 180 sec R-filter                          2 x 180 sec V-filter Coordinates: RA: 11:51:38.24  DEC: +00:49:46.4  (J2000.0) Magnitude: g = 19.0 Observing period: Apr + May + 1st half of June TCS catalogue: wold_p35.cat
Name: SDSS J124035.81-002919.4 Exposure time: 2 x 180 sec R-filter                          2 x 180 sec V-filter Coordinates: RA: 12:40:35.81  DEC: -00:29:19.4  (J2000.0) Magnitude: g = 18.0 Observing period: Apr + May + 1st half of June TCS catalogue: wold_p35.cat
Name: SDSS J172759.15+542147.0 Exposure time: 2 x 180 sec R-filter                          2 x 180 sec V-filter Coordinates:  RA: 17:27:59.15  DEC: +54:21:47.0  (J2000.0) Magnitude: g = 19.3 Observing period: 2nd half of June + July + Aug + Sep TCS catalogue: wold_p35.cat
Name: SDSS J170246.09+602818.9 Exposure time: 2 x 180 sec R-filter                          2 x 180 sec V-filter Coordinates: RA: 17:02:41.80  DEC: +60:28:11.5  (J2000.0) Magnitude: g = 18.2 Observing period: 2nd half of June + July + Aug + Sep TCS catalogue: wold_p35.cat	NB. The qso is off-center deliberately
Name: SDSS J215658.30+110343.1 Exposure time: 2 x 180 sec R-filter                          2 x 180 sec V-filter Coordinates:  RA: 21:56:58.30  DEC: +11:03:43.1  (J2000.0) Magnitude: g = 17.6 Observing period: 2nd half of June + July + Aug + Sep TCS catalogue: wold_p35.cat

Weather constraints:

The programme can be done under conditions of reduced transparency (such as thin cirrus), but if the seeing is > 1.5-1.7 arcsec, please abandon.

Requested images:

Calibration files	3 bias frames - can be obtained during daytime 3 flat field images in V-filter (obtained at twilight) 3 flat field images in R-filter (obtained at twilight) (If there is little time to do flats, please consider taking StanCam R-flats during sunset and V-flats during sunrise, or vice versa)	Instructions
Science frames	Of the targets to be observed during your run (see schedule):    2 x 180 sec in V-filter with 15" offset between exposures    2 x 180 sec in R-filter with 15" offset between exposures	Instructions

Observing instructions:

All the observations should be done with StanCam

If you are using ALFOSC
If you are using NOTCam
If you are using MOSCA

How to take:    bias images
                      twilight flat fields
                      science images

Bias images (can be taken in the afternoon):

To make three bias frames, type in BIAS:
    BIAS> autosave+ -- enable autosave
    BIAS> rempath /data/service/calib -- set remote path for data storage
    BIAS> remsave+ --enable remote save
    BIAS> obj bias -- name object
    BIAS> mdark 0 3 -- take three bias images with exposure time zero
    BIAS> remsave-  -- disable autosave

Twilight flats:

To make three twilight V and R flat field images:
(Evening twilight: V first, then R. Morning twilight: R first, then V -- why?)
    On the TCS, type:
        CAT Command: read blankstmp -- load the blanks catalogue
        Select a suitable blank field with the keypads 1,7 or Prev, Next -> PresetToSel
        Command: ccd-fil 4 -- this puts the R-filter in position
        Command: c-p-c -- this puts the camera on position
    In BIAS, type:
        BIAS> autosave+ -- enable autosave
        BIAS> rempath /data/service/calib -- set remote path
        BIAS> remsave+ -- enable remote save for data storage
        BIAS> obj R flats -- name object
    Repeat the following command (3 times) with suitable exposure times to give ~20000 ADU. Between each exposure, hit one of the arrow keys on the TCS to offset the telescope between each exposure
        BIAS> exp [exposure time in seconds] -- take the flat
    On the TCS, type:
        Command: ccd-fil 3 -- this puts the V-filter in position
        Command: c-p-c -- this puts the camera on position
    In BIAS, type:
        BIAS> obj V flats - name the object
    Repeat the following command (3 times) with suitable exposure time to give ~20000 ADU. Between each exposure, hit one of the arrow keys on the TCS to offset the telescope between each exposure
        BIAS> exp [exposure time in seconds] -- take the flat
        BIAS> remsave- -- disable remote save

Science images:

If ALFOSC or FIES are in use please make sure to switch off the ALFOSC/FIES calibration lamps.

To take images of the science target:
    On the TCS, type:
        Command: field-r 0 -- this gives you the start setup of StanCam
        Command: c-p-c -- put the camera on position
        Command: ccd-fil 3 -- puts the V-filter in position

 To load the science targets load the catalog on TCS:
        To find which object to observe, look at the schedule
        Read-Catalogue -> Command: /catalogue/wold_p35.cat -> PresetToSel
        Look at the guide probe screen and move the star box onto the guide star
        Start autoguiding by typing in TCS:
            Command: ag-on

        Make sure the telescope is at the correct focus. If you have not determined the telescope focus yet look
        for instructions at the `If you are using...' pages linked above or the StanCam focusing page.

        Now run the corresponding scripts for the target by typing in BIAS:
            BIAS> run wold1151_V.run [note that the 4-digit part of the script name is different for each target]
            This script executes the following commands:
               autosave+
               rempath /data/too/P35/Wold
               remsave+
               obj [name of object, for instance sdss115138]
               resetxy
               exp 180
               teloffset 10 0
               exp 180

        Change to the R-filter by typing on TCS:
            Command: ccd-fil 4
        In BIAS, do the following:
            BIAS> run wold1151_R.run [note that the 4-digit part of the script name is different for each target]
            This script will execute the same commands as the woldxxxx_V.run script, except that the teloffset is
            in the opposite direction

        Stop autoguiding by typing on TCS:
            Command: ag-off
        Go back to the setup of the camera you are using for your programme.
        Type on TCS:
            Command: c-p-p
        If you are using NOTCam or MOSCA, type on TCS:
            Command: field-r -90
        If you are using ALFOSC, type on TCS:
            Command: field-r +90
            

Observing schedule:

Dato	Apr	May	Jun	Jul	Aug	Sep
1	x	SDSS 1240	x	x	SDSS 1727	x
2	x	SDSS 1140	SDSS 1140	x	SDSS 1702	SDSS 1702
3	SDSS 1140	x	SDSS 1151	x	SDSS 2156	x
4	SDSS 1151	SDSS 1151	SDSS 1240	x	SDSS 1727	x
5	SDSS 1240	SDSS 1240	SDSS 1140	SDSS 1702	SDSS 1702	x
6	SDSS 1140	SDSS 1140	SDSS 1151	SDSS 2156	SDSS 2156	SDSS 2156
7	SDSS 1151	SDSS 1151	SDSS 1240	SDSS 1727	SDSS 1727	SDSS 1727
8	SDSS 1240	SDSS 1240	SDSS 1140	SDSS 1702	x	SDSS 1702
9	SDSS 1140	SDSS 1140	SDSS 1151	x	x	SDSS 2156
10	SDSS 1151	SDSS 1151	SDSS 1240	x	x	SDSS 1727
11	SDSS 1240	x	SDSS 1140	x	x	SDSS 1702
12	SDSS 1140	SDSS 1240	SDSS 1151	x	x	SDSS 2156
13	SDSS 1151	SDSS 1140	SDSS 1240	x	x	SDSS 1727
14	SDSS 1240	SDSS 1151	SDSS 1140	x	SDSS 1702	SDSS 1702
15	SDSS 1140	SDSS 1240	SDSS 1151	x	SDSS 2156	x
16	SDSS 1151	SDSS 1140	SDSS 1240	x	x	x
17	SDSS 1240	SDSS 1151	x	SDSS 1727	x	SDSS 2156
18	SDSS 1140	SDSS 1240	x	SDSS 1702	x	SDSS 1727
19	SDSS 1151	SDSS 1140	SDSS 1702	SDSS 2156	x	SDSS 1702
20	SDSS 1240	SDSS 1151	SDSS 2156	SDSS 1727	x	x
21	x	SDSS 1240	x	SDSS 1702	x	SDSS 2156
22	x	SDSS 1140	x	SDSS 2156	x	SDSS 1727
23	SDSS 1140	SDSS 1151	x	SDSS 1727	x	SDSS 1702
24	SDSS 1151	x	x	SDSS 1702	x	SDSS 1727
25	SDSS 1240	x	SDSS 1727	SDSS 2156	SDSS 1727	SDSS 1702
26	SDSS 1140	x	SDSS 1702	SDSS 1727	SDSS 1702	SDSS 2156
27	SDSS 1151	x	SDSS 2156	SDSS 1702	SDSS 2156	SDSS 1727
28	SDSS 1240	x	SDSS 1727	SDSS 2156	SDSS 1727	SDSS 1702
29	SDSS 1140	SDSS 1240	x	SDSS 1727	SDSS 1702	SDSS 2156
30	SDSS 1151	x	x	SDSS 1702	SDSS 2156	SDSS 1727
31		x		SDSS 2156	SDSS 1727	SDSS 1702

April + May + 1st half of June	SDSS J114008.71+030711.4 SDSS J115138.24+004946.4 SDSS J124035.81-002919.4
2nd half of June + July + Aug + Sep	SDSS J172759.15+542147.0 SDSS J170246.90+602818.9 SDSS J215658.30+110343.1

Note about twilight flats: It is a good idea to start with the bluer filters when the sun is setting, and change to progressively redder filters as the sky is getting darker. This will allow you to use the twilight time more efficiently, as you are able to take twilight flats in the redder filters when the sky is darker. Reverse during sunrise. 

Contacts: