Multiwavelength Campaign of the Extraordinary Novalike Cataclysmic Variable BZ Camelopardalis

This is a DD proposal which could not be submitted during the usual Cycle 31 submission window and cannot wait until the next cycle. If the target cannot be observed during the last week or two of cycle 31, it can be considered for the first week of Cycle 32 as explained in the proposal. 126736800 Assigned ID: 5920 ----- Attempting Submission 1 (Fri May 31 18:44:28 GMT 2024) ----- HST Phase I Proposal 5920 successfully submitted. Receipt: # 5920-1 This re-submission includes small adjustments and corrections which were suggested by the contact scientist. 1383493045 ----- Attempting Submission 1 (Sun Jul 21 22:34:38 GMT 2024) ----- HST Phase II Proposal 17695 successfully submitted. Receipt: # 17695-1 ----- Attempting Submission 2 (Wed Jul 24 19:00:23 GMT 2024) ----- Multiwavelength Campaign of the Extraordinary Novalike Cataclysmic Variable BZ Camelopardalis Novalikes (NLs) are interacting binaries where a white dwarf accretes at a high rate by means of an accretion disk. They exhibit outflows and constitute important laboratories to study the effects of high accretion rate on accretion physics. NLs show hot optically thin plasma emission in the X-rays that can be characterized with advective hot flows (ADAF-like) and particularly BZ Cam is a typical example. The standard disk is found inadequate to model NLs in the UV. Optically thin radiatively inefficient (advective) hot flows in nonmagnetic NLs and advective heating of WDs are important to understand as they influence accretion, evolution, and thermonuclear runaways that lead to nova explosions. We have approved Chandra HETG time for BZ Cam to determine the ionization conditions in the X-ray emitting plasma via emission line diagnosis for studying the radiatively inefficient hot accretion flows (ADAF-like) in this source with extrapolation to other NLs. It will also detect warm absorber effects for the first time in the X-rays via absorption line analysis. Thus, we started a multiwavelength campaign on BZ Cam for a comparative study and a global understanding of accretion physics in NLs. In this regard, we want to observe BZ Cam using the COS instrument contemporaneously with or very close to the Chandra Observations which is right before cycle 32 starts. We plan radio observations and further ground-based optical spectroscopic observations (DDT) using TFOSC at 1.5m RTT150 (Turkish National Observatory) and fast multi-color photometry with OPTICAM (GTO) at 2.1m telescope in SPM National Observatory (Mexico). In the last week, TESS observations have also been approved for the multiwavelength campaign of BZ Cam. SAFETY OF THE COS INSTRUMENT. In the phase I of this DD proposal we requested COS G130M 1055 and COS G140L 1105 spectra of the nova-like BZ Cam. These are two of theCOS/FUV Science default modes of the COS intrument following the COS2025 policy. Therefore, our proposed observations do adhere to the restritions set forth by the COS2025 policy to prolong the lifetime of the COS/FUV detector. The magnitude of BZ Cam is usually between 12 and 13.5, and can sometimes be found at 11.5 and as low as 14.5. It doesn't undergo outburst. As a VY Scl type of nova-like it is found mostly in a high state between v=12 and 13.5 and occasionally drop to 14.5 into a low state. The IUE archival spectra show that the continuum flux level in the FUV near 1400A reaches a maximum of 3.e-13 erg/s/cm**2/A and a minimum of about 0.7e-13 erg/s/cm**2/A, while most of the time it is found at amplitude of about 1.e-13 erg/s/cm**2/A. It has some GHRS spectra which were obtained for the study of the absorption and emission lines and from these spectra we find that It exhibits some emission lines reaching a maximum of 6.e-13 erg/s/cm**2/A. There is some orbital variability which is important for the science but, it too doesn't cause any concern for the instrument. It has a FUSE spectrum going down the Lyman limit (900 A) which show a continuum flux level of 1.e-13 erg/s/cm**2/A with ISM absorption. We have used the lowest continuum flux level of 7e-14 erg/s/cm**2/A for runs of the ETC assuming a flat continuum. For the COS G130M (1055) configuration a S/N of 10 at 1100A is obtained for 1755 sec of exposure time (COS.sp.1923942). Since the FUV source is moderately weak, we do not need to worry about the buffer time. For the COS G140L (1105A) configuration a S/N of 20 near 1800 A is obtained for an exposure time of 1308 s (COS.sp.1923946). To this time we add the guide star time, the target acquisition time, and the instrument overhead, namely 1620 s. WIth an estimated visibility time of about 55 min or 3,300s, this justified our original request for a total of 2 orbits, one for each COS configuration, in our phase I. In order to check whether the higher flux of 3.e-13 erg/s/cm**2/A might be problem for the COS instrument/detector, we ran an ETC for the COS G130M (1055) configuration assuming a flat flux of 3.e-13 erg/s/cm**2/A . The 2 emission lines: one with 6.e-13 erg/s/cm**2/A at 1550A (FWHM=10 A, Carbon iv line) and the other with 5.e-13 erg/s/cm**2/A at 12616 A (FWHM=6A, Hydrogen Lyman alpha line) are outside the detector range and are not included. We obtained for a 2000s exposure time a SNR=22 (1100A) with no warning. COS.sp.1927866 We perform a similar ETC run for the COS G140L (1105) configuration WITH the includsion of the 2 emission lines mentioned above, and obtained a HARD WARNING that the count rate on Segment A is larger than 40 percent of the 15,000 counts/s limit. Therefore we checked which continuum flux level is too much for the instrument. For the flat continuum with 2.5e-13 erg/s/cm**2/A we do get a hard warning as the CR is 6092 which is larger than the 6000 allowed (40 percent of the 15,000). COS.sp.1927520 For a flat continuum with 2.4e-13 erg/s/cm**2/A no hard warning as the CR drops below 6000 at 5858 (buffer 402 s). COS.sp.1927619 So it seems that the threshold is from 2.4 to 2.5 e-13 erg/s/cm**2/A. The limit of 15,000 CR is reached for a continuum flux level of 6.28e-13 erg/s/cm**2/A (COS.sp.1927733). The minimum observed UV flux from IUE is about 0.5 e-13 and the maximum is at 3.e-13. The visual magnitude has been observed to be between 11.5 and 14.5 with an average of 13 +/- 1.5 . A change of a factor 6 from 0.5e-13 (minimum) to 3.0e-13 (maximum) in the UV would correspond to a change in magnitude of ~2 (since a change of 1 corresponds to a factor 2.5). So, being on safe side,we write the following relation between visual magnitude and continuum flux level: V ==> UV Flux (in units of 1.e-13 erg/s/cm**2/A) 12.00 ==> 3.00 12.25 ==> 2.44 12.30 ==> LIMIT !! 12.5 ==> 1.94 13.00 ==> 1.225 14.00 ==> 0.50 The limit of 15,000 CR is reached for a continuum flux level of 6.28e-13 erg/s/cm**2/A (COS.sp.1927733) which correspond to a magnitude of V=11.16 (which has not been observed so far). Such that if the visual magnitude is 12.40 or larger, it is safe to observe, if it is 12.30 or smaller it is not safe. In the last few years the visual magnitude was above 12.5, averaged at 13.0 +/- 0.2 (where the +/- 0.2 is due to orbital modulation). We can monitor the target through the AAVSO (American Association of Variable Stars Observers), which is something that is done regularly (and continuously) and make sure the target is observed only if it is safe to do so. In the ETC form we now input the most likely (flat) continuum flux level of 1.5e-13 erg/s/cm**2/A for the G140L configuration (COS.sp.1928288) for a 2000 sec exposure time (4x500) including the above mentioned emission lines. This gives a buffer time of 630 sec, taking 2/3 of it we use 400 sec as the actual buffer time. For the G130M configuration, using the same flux, the ETC gives a buffer fill time of 2400 sec (2300sec for Seg A, 2500 sec for Seg B), 2/3 of this is 1600 sec (COS.sp.1928290; note that the above mentioned emission lines are not in the band pass and do not affect the run). TIMING/SCHEDULING OF THE OBSERVATIONS. Since our target is part of a multi-wavelength campaign, with X-ray Chandra observation the last week of September 2024, we request the HST observations to be concurrent to the Chandra observation. Namely we request the HST observations to be carried out between 23 Sep 2024 and 30 Sep 2024 (included). This is the last week of Cycle 31. If this time is impossible, one week before and one week after the last week of September 2024 can be used. We request one visit where the two COS observations/exposures are taken directly one after the other. PI Godon is a full-time research faculty and spends 100 percent of his effort in research. He has expertise in HST data reduction, including COS, STIS, FOS and GHRS with more than 2 dozen refereed papers published in the last decade on data analysis of HST FUV spectral data. He has expertise in accretion disks, white dwarf stars, and their boundary layers in cataclysmic variable. In the last two decades he has used the suite of codes TLUSTY and SYNSPEC (I. Hubeny) to generate theoretical spectra of white dwarfs and accretion disks in the UV and optical for the spectral analysis and modeling of cataclysmic variable UV and optical data. CoI Sion has leading expertise in the structure and evolution of accreting white dwarfs in interacting binaries as well as the physical processes and evolution of single white dwarfs. He has been the PI on numerous successful HST proposals beginning in Cycle 2 and continuing through Cycle 25 and is the lead author or co-author on 84 HST refereed publications in major journals. CoI Solen Balman is a researcher in the field of high energy astrophysics, especially compact objects, cataclysmic variables, novae and X-ray binary systems for about 25 years in Turkey and abroad. She is an expert in spectral, spatial and timing analysis of data mainly in the X-rays (ROSAT, ASCA, BeppoSAX, RXTE, Suzaku, Chandra, XMM-Newton, INTEGRAL, NuSTAR, NICER Missions) out to Gamma-rays and optical wavelengths. CoI Schlegel research interests are in the astrophysics of interacting binary stars and Supernovae, particularly in the high-energy bands, but also extending across the EM spectrum. Schlegel's publications number 130+ with 42 papers focused on cataclysmic variables in the optical, UV, X-ray, and gamma-ray bands. CoI Jeremy Drake research interest is in the study of high energy aspects of stellar physics and how they impact star and planet formation, stellar evolution, and planetary radiation environments.He is an expert on stellar outer atmospheres and magnetic activity, novae, and on UV, EUV, and X-ray emission of stars and stellar systems. He has more than two decades of experience working with Chandra and XMM-Newton data and was an instrument scientist for Chandra Observatory. CoI Patrick Woudt research insterests are in Cataclysmic Variables, Ultra-compact binaries, and Radio transient surveys. Stellar Physics and Stellar Types 0 false SUPPORTED STAR NOVA-LIKE NO This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM.This object was generated by the targetselector and retrieved from the SIMBAD database. BZ-CAM J2000 J2000 continuum: minimum 7.e-14 erg/s/cm**2/A, maximum 3.e-13 erg/s/cm**2/A ; emission line 6.e-13 erg/s/cm**2/A COS/FUV Spectroscopic No No G130M 1055 COS/FUV Spectroscopic No No G140L 1105 /System/Volumes/Data/solaris/user1/royle/OP-cache/17695-v01.xml 1727992692487 The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. 1727177634000 275.8357410156402 (Tic-Visit :proposal-id 17695 :visit-id "01" :proposal-version -1 :trans-version "20240627" :date "03-Oct-2024 17:58:12.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 556848 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17695 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17695 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2803 :al-overhead-at-end 0 :internal-dur-at-end 372 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3184 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17695 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2803 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3184 :pcs-gap 0 ) true 2 0 /System/Volumes/Data/solaris/user1/royle/OP-cache/17695-v51.xml 1727992749483 The scheduling data was generated by CASM 32.1.3. CASM was run in Phase II mode. 1728938417000 255.9459361920808 (Tic-Visit :proposal-id 17695 :visit-id "51" :proposal-version -1 :trans-version "20240627" :date "03-Oct-2024 17:59:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 417584 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17695 :visit-id "51" :obset-id "51" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17695 :visit-id "51" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2803 :al-overhead-at-end 0 :internal-dur-at-end 369 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3184 :pcs-gap 0 ) true 1 0 /System/Volumes/Data/solaris/user1/royle/OP-cache/17695-v52.xml 1731011807642 The scheduling data was generated by CASM 32.1.3. CASM was run in Phase II mode. 1734576609000 192.67633365489536 (Tic-Visit :proposal-id 17695 :visit-id "52" :proposal-version -1 :trans-version "20240627" :date "07-Nov-2024 15:36:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 417584 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17695 :visit-id "52" :obset-id "52" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17695 :visit-id "52" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2803 :al-overhead-at-end 0 :internal-dur-at-end 369 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3184 :pcs-gap 0 ) true 1 0 /private/var/folders/8t/mg1bkfyj20xf2vfc_9vyhfs80006z1/T/OPVisit11643764600080440338.xml 1740085516915 The scheduling data was generated by CASM 33.0. CASM was run in Phase II mode. Repeat of observations that have been repeatedly lost from visit 01 (Tic-Visit :proposal-id 17695 :visit-id "53" :proposal-version -1 :trans-version "20241217" :date "20-Feb-2025 16:05:16.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 417584 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17695 :visit-id "53" :obset-id "53" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17695 :visit-id "53" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2803 :al-overhead-at-end 0 :internal-dur-at-end 369 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3184 :pcs-gap 0 ) true 1 0