The EVLA Nova (ENova) Project: First Results

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1 The EVLA Nova (ENova) Project: First Results Miriam Krauss (NRAO) The ENova Team: Laura Chomiuk (NRAO, CfA); Jennifer Sokoloski (Columbia); Michael Rupen, Nirupam Roy, Amy Mioduszewski (NRAO); Gregg Hallinan (National U. of Ireland, Galway); Tim O Brien (U. of Manchester); Mike Bode (Liverpool John Moores U.); Jill Knapp (Princeton U.); Stewart Eyres (U. of Central Lancashire)

2 Classical Novae: Introduction Z Camelopardalis (NASA/JPL-Caltech, GALEX)

3 Radio emission from novae: Observational motivation Novae are nearby laboratories for accretion/ejection physics Long-lasting emission in radio; evolution is slower than at other frequencies Thermal bremsstrahlung easy to model; can derive physical parameters Ejected material is optically thick at much lower densities Can be used to get mass estimates but don t agree with optical observations or theory

4 Radio emission from novae: Light curves and modeling Linear velocity gradient (a.k.a. Hubble flow ) model Optically thick rise: Sν ν 2 Freely expanding, isothermal shell

5 Radio emission from novae: Light curves and modeling Linear velocity gradient (a.k.a. Hubble flow ) model Mej = 4.5 x -5 M D = 0.65 kpc v2 = 990 km/s v1 / v2 = 0.05 Hjellming et al. 1979

6 The ENova Project: A new era of observations EVLA + emerlin + VLBI: all galactic novae Monitoring of new, nearby (< 3 kpc) novae (currently underway) improved sensitivity broad frequency coverage fast response Imaging of recent novae (proposed observations) morphology and spectral properties of radio remnants will tie to interpretation of light curves Hjellming et al. 1979

7 The ENova Project: Symbiotic system with Mira secondary dense circumbinary medium D 2.7 kpc First nova with detected gamma-ray emission Early Merlin observations show resolved shell VLBI detections V407 Cyg F γ ( 7 cm 2 s 1 ) Optical (mag) Rate ( 2 s 1 ) Fig. 2. Fermi-LAT g-ray counts (200 MeV to 0 GeV) map from March 18:00 to 29 March 00:00 20 in the region around the positionnew of the Mexico g-ray Symposium nova source V407 Cyg (marked Nov. 5, by 20 the black cross) at Galactic longitude l = , g) 5 XRT 0.3 kev LAT >0 MeV Days since March 20 R C The Fermi-LAT Collaboration, 20 V Downloaded from on August 20, 20

!<%+37%/56%O4)8/Te!M>%,+(3)/A76*% %/56%AN,K%8)B/61=%9DJJEKJ_%3,<=% %-.//.,%2+36B%*5.4*%/56%N)*A+B% 3)/A76*%81.,%VV!OM%.

,8% % % 5 GHz 500 AU D% K% I% c+'%dd% V407 Cyg F γ ( 7 cm 2 s 1 ) Optical (mag) Rate ( 2 s 1 ) 12 8 6 4 2 7 8 9 11 25

8 !<%+37%/56%O4)8/Te!M>%,+(3)/A76*% %/56%AN,K%8)B/61=%9DJJEKJ_%3,<=% %-.//.,%2+36B%*5.4*%/56%N)*A+B% 3)/A76*%81.,%VV!OM%.-*61N61*=% The ENova Project: $%&'()*+,)-./&)0)12+3%)4"5.675)%&.,8% % % 5 GHz 500 AU D% K% I% c+'%dd% V407 Cyg F γ ( 7 cm 2 s 1 ) Optical (mag) Rate ( 2 s 1 ) XRT 0.3 kev LAT >0 MeV Days since March 20 R C V Downloaded from on August 20, 20 K% Fig. 2. Fermi-LAT g-ray counts (200 MeV to 0 GeV) map from March 18:00 to 29 March 00:00 20 in the region around the position of the New g-ray Mexico nova Symposium 5 source V407 Cyg (marked by the black cross) at Galactic c+'%dj% longitude l = , eg) The Fermi-LAT Collaboration, 20

9 density of the RG stellar wind and atmosphere surrounding the I% nova shell, which depend on two poorly constrained parameters: (i) the WD-RG separation (a) and (ii) the RG mass-loss rate in the wind (M W ). As we will discuss shortly, the detection of the g-ray flux within 1 day of the optical detection of the nova, a peak duration of 3 to 4 days, and subsequent decay within 15 days after the optical nova can be modeled as emission from the nova shell in a dense environment and The ENova Project: V407 Cyg 5 GHz eg) Rate ( s ) Optical (mag) Fγ ( cm s ) ast day with a significant detection x-ray flux, can be explained qualitatively as a ariable g-ray source was 25 March, geometrical effect of the nova-shell evolution. #$%&'()*+,)-./&)0)12+3%)4"5.675)%&.,8% The measured optical peak magnitude of 7 of a total lifetime of activity of 2 ng an active period (14) from V407 Cyg (9) over 1 day implies an energy reo 29 March 00:00, we obtained a lease of 3 42 ergs at visible frequencies (Fig. 2) from the cumulative ex0.040 offset from the optical po12 Fig. 1. Light curves of V407 Cyg Cyg, which is within the LAT 95% LAT in g-rays from the Fermi-LAT (top), cle (radius = ). The average >0 MeV 8 D% optical (middle), c+'%kk% and x-rays from c+'%dd% c+'%dj% y distribution (SED) of the Fermi6 (bottom). Vertical bars indi'% during the defined active pe- Swift 500 AU urce 4 cate500 1s AU statistics errors for all data described with an exponentially % 2 (the errors are smaller than the law model (see SOM) withd%a flux points in thek%optical section). For (4.4 T 0.4) 7 photons cm 2 s 1 the g-ray data, gray arrows indi7 %l source significance of 18.1s). A cate 2s upper limits, and horizontal RC 8 o test indicates that the addition of bars indicate the 1-day binning. In 9 l cut-off improves the fit at the 4.9s the optical section, unfiltered (black), V d with a simpler single power-law RC (red), and V (green) band magni11 nd no evidence for spectral varia- tudes are shown (see SOM). The 25 duration of the active g-ray period vertical dashed blue line indicates XRT the epoch of the optical nova detec0.3 kev ur analysis of the data from the 2 20 I% he active period (29 March to 12 tion; the g-ray peak occurred 3 to 15 vely gives a significance of only 4 days later. Fg, g-ray flux; XRT, 7 Swift X-ray Telescope. x upper limit of 0.8 photons 5 icating that the flux has declined l of detectability. Overall, the g-ray Days since March 20 test at earlier times, consistent with avior of V407 Cyg. The coincident d the observed correlated variability Fig. 2. Fermi-LAT g-ray counts (200 MeV optical nova is the source of the to 0 GeV) map from March 18:00 The Fermi-LAT Collaboration, 20 E" flux. GD# % *.B+1%,+**6*=% :68% D% *A((6*/% +3% :;%,+**EB.**% 1+/6%% to 29 March 00:00 20 in the region ray lines and continuum E$ emission around the position of the g-ray nova New Mexico Symposium GJ?D# *.B+1%,+**6*T'1% L,T*=% >5)*% 0.AB7% 8)BB% +% 5 1-MeV energies have %been con- source V407 Cyg (marked +/% by thegkd% black c+'%dj% KK% but then.ba,6% Fermi-LAT detection of cross) at Galactic longitude l = , 0.116*2.37)3(% /.% /56% *)\6%.8% /56% 1+7).% *.A6% 4)/5% Downloaded from on August 20, 20 served K%E%K@VOO%2.*)/).3%9168%J<k% between 13 to 14 March, 3 can be explained by p decay g-rays from proton6!<%+37%/56%o4)8/te!m>%,+(3)/a76*% the initial g-ray detection, and with proton (pp) collisions or inverse Compton (IC) 5%/56%AN,K%8)B/61=%9DJJEKJ_%3,<=% I%E%2.*)/).3%.8%/56%0.,2+0/%!UFY% 7 photons cm 2 s 1) that was scattering of infrared photons from the RG by 6%-.//.,%2+36B%*5.4*%/56%N)*A+B% 0.,2.363/%76/60/67%4)/5%/56% hat observed on March by a electrons. In both of these scenarios, the g-ray light he dataxa1.26+3%!ufy%z6/4.1l%9168%$<=% was analyzed up to mid- curve, in conjunction with the delayed rise of the (3)/A76*%81.,%VV!OM%.-*61N61*=%

10 The ENova Project: V407 Cyg EVLA observations/modeling Observations at 1.5, 1.8, 4.8, 7.9, 19, 25, 41, 45 GHz OSRO1 mode observing (2 x 128 MHz spectral windows per band) Light curves: days Spectral index: 0.8 at earliest epochs; ~0.1 at latest

11 The ENova Project: V407 Cyg EVLA observations/modeling Best-fit linear velocity gradient model: 7.0, 7.9, 19, and 25 GHz Light curves: days Observations at 1.5, 1.8, 4.8, 7.9, 19, 25, 41, 45 GHz Ultimately, very complex system must consider multi-wavelength data

12 The ENova Project: V1723 Aql a simpler source? Discovered Sept. 11; EVLA observations began Sept GHz bandwidth Highly extincted; source not previously known Early EVLA data: rising flux; α < 2 D 3 kpc (vej = 1500 km/s, optically thick at 30 GHz) Swift X-ray detection on day 40 Continued observations: how will radio source develop?

13 The ENova Project: Conclusions & future prospects First complete, rapid-response, multifrequency radio monitoring of Galactic novae Already, data are challenging standard models Imaging will be very important! Will provide some of the highest-quality radio data ever gathered An exciting time for theory and interpretation!

arxiv: v2 [astro-ph.sr] 18 Jul 2013

arxiv: v2 [astro-ph.sr] 18 Jul 2013 STELLA NOVAE: FUTURE AND PAST DECADES ASP Conference Series, Vol. **Volume Number** P. A. Woudt and V. A. R. M. Ribeiro, eds c 2013 Astronomical Society of the Pacific Shocks and Ejecta Mass: Radio Observations